kolmck/Addons/KOLMath.pas
dkolmck 19cb111bcd v3.i
git-svn-id: https://svn.code.sf.net/p/kolmck/code@78 91bb2d04-0c0c-4d2d-88a5-bbb6f4c1fa07
2010-10-12 17:54:18 +00:00

1846 lines
51 KiB
ObjectPascal

{=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
KKKKK KKKKK OOOOOOOOO LLLLL
KKKKK KKKKK OOOOOOOOOOOOO LLLLL
KKKKK KKKKK OOOOO OOOOO LLLLL
KKKKK KKKKK OOOOO OOOOO LLLLL
KKKKKKKKKK OOOOO OOOOO LLLLL
KKKKK KKKKK OOOOO OOOOO LLLLL
KKKKK KKKKK OOOOO OOOOO LLLLL
KKKKK KKKKK OOOOOOOOOOOOO LLLLLLLLLLLLL
KKKKK KKKKK OOOOOOOOO LLLLLLLLLLLLL
Key Objects Library (C) 2000 by Kladov Vladimir.
mailto: vk@kolmck.net
Home: http://kolmck.net
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-}
{
This code is grabbed from standard math.pas unit,
provided by Borland Delphi. This unit is for working with
engineering (mathematical) functions. The main difference
is that err unit specially designed to handle exceptions
for KOL is used instead of SysUtils. This allows to make
size of the executable smaller for about 5K. though this
value is insignificant for project made with VCL, it can
be more than 15% of executable file size made with KOL.
}
{*******************************************************}
{ }
{ Borland Delphi Runtime Library }
{ Math Unit }
{ }
{ Copyright (C) 1996,99 Inprise Corporation }
{ }
{*******************************************************}
unit kolmath;
{ This unit contains high-performance arithmetic, trigonometric, logorithmic,
statistical and financial calculation routines which supplement the math
routines that are part of the Delphi language or System unit. }
{$N+,S-}
{$I KOLDEF.INC}
interface
uses {$IFNDEF MATH_NOERR} err, {$ENDIF} kol;
const { Ranges of the IEEE floating point types, including denormals }
MinSingle = 1.5e-45;
MaxSingle = 3.4e+38;
MinDouble = 5.0e-324;
MaxDouble = 1.7e+308;
MinExtended = 3.4e-4932;
MaxExtended = 1.1e+4932;
MinComp = -9.223372036854775807e+18;
MaxComp = 9.223372036854775807e+18;
{-----------------------------------------------------------------------
References:
1) P.J. Plauger, "The Standard C Library", Prentice-Hall, 1992, Ch. 7.
2) W.J. Cody, Jr., and W. Waite, "Software Manual For the Elementary
Functions", Prentice-Hall, 1980.
3) Namir Shammas, "C/C++ Mathematical Algorithms for Scientists and Engineers",
McGraw-Hill, 1995, Ch 8.
4) H.T. Lau, "A Numerical Library in C for Scientists and Engineers",
CRC Press, 1994, Ch. 6.
5) "Pentium(tm) Processor User's Manual, Volume 3: Architecture
and Programming Manual", Intel, 1994
+6)������ �������, "�������������� ����� ��� �������������", ������������ ���.,
2004
All angle parameters and results of trig functions are in radians.
Most of the following trig and log routines map directly to Intel 80387 FPU
floating point machine instructions. Input domains, output ranges, and
error handling are determined largely by the FPU hardware.
Routines coded in assembler favor the Pentium FPU pipeline architecture.
-----------------------------------------------------------------------}
function EAbs( D: Double ): Double;
function EMax( const Values: array of Double ): Double;
function EMin( const Values: array of Double ): Double;
function ESign( X: Extended ): Integer;
function iMax( const Values: array of Integer ): Integer;
function iMin( const Values: array of Integer ): Integer;
function iSign( i: Integer ): Integer;
{ Trigonometric functions }
function ArcCos(X: Extended): Extended; { IN: |X| <= 1 OUT: [0..PI] radians }
function ArcSin(X: Extended): Extended; { IN: |X| <= 1 OUT: [-PI/2..PI/2] radians }
{ ArcTan2 calculates ArcTan(Y/X), and returns an angle in the correct quadrant.
IN: |Y| < 2^64, |X| < 2^64, X <> 0 OUT: [-PI..PI] radians }
function ArcTan2(Y, X: Extended): Extended;
{ SinCos is 2x faster than calling Sin and Cos separately for the same angle }
procedure SinCos(Theta: Extended; var Sin, Cos: Extended) register;
function Tan(X: Extended): Extended;
function Cotan(X: Extended): Extended; { 1 / tan(X), X <> 0 }
function Hypot(X, Y: Extended): Extended; { Sqrt(X**2 + Y**2) }
{ Angle unit conversion routines }
function DegToRad(Degrees: Extended): Extended; { Radians := Degrees * PI / 180}
function RadToDeg(Radians: Extended): Extended; { Degrees := Radians * 180 / PI }
function GradToRad(Grads: Extended): Extended; { Radians := Grads * PI / 200 }
function RadToGrad(Radians: Extended): Extended; { Grads := Radians * 200 / PI }
function CycleToRad(Cycles: Extended): Extended; { Radians := Cycles * 2PI }
function RadToCycle(Radians: Extended): Extended;{ Cycles := Radians / 2PI }
{ Hyperbolic functions and inverses }
function Cosh(X: Extended): Extended;
function Sinh(X: Extended): Extended;
function Tanh(X: Extended): Extended;
function ArcCosh(X: Extended): Extended; { IN: X >= 1 }
function ArcSinh(X: Extended): Extended;
function ArcTanh(X: Extended): Extended; { IN: |X| <= 1 }
{ Logorithmic functions }
function LnXP1(X: Extended): Extended; { Ln(X + 1), accurate for X near zero }
function Log10(X: Extended): Extended; { Log base 10 of X}
function Log2(X: Extended): Extended; { Log base 2 of X }
function LogN(Base, X: Extended): Extended; { Log base N of X }
{ Exponential functions }
{ IntPower: Raise base to an integral power. Fast. }
//function IntPower(Base: Extended; Exponent: Integer): Extended register;
// -- already defined in kol.pas
{ Power: Raise base to any power.
For fractional exponents, or |exponents| > MaxInt, base must be > 0. }
function Power(Base, Exponent: Extended): Extended;
{$IFNDEF _D6orHigher}
function Trunc( X: Extended ): Int64;
{$ENDIF}
{ Miscellaneous Routines }
{ Frexp: Separates the mantissa and exponent of X. }
procedure Frexp(X: Extended; var Mantissa: Extended; var Exponent: Integer) register;
{ Ldexp: returns X*2**P }
function Ldexp(X: Extended; P: Integer): Extended register;
{ Ceil: Smallest integer >= X, |X| < MaxInt }
function Ceil(X: Extended):Integer;
{ Floor: Largest integer <= X, |X| < MaxInt }
function Floor(X: Extended): Integer;
{ Poly: Evaluates a uniform polynomial of one variable at value X.
The coefficients are ordered in increasing powers of X:
Coefficients[0] + Coefficients[1]*X + ... + Coefficients[N]*(X**N) }
function Poly(X: Extended; const Coefficients: array of Double): Extended;
{-----------------------------------------------------------------------
Statistical functions.
Common commercial spreadsheet macro names for these statistical and
financial functions are given in the comments preceding each function.
-----------------------------------------------------------------------}
{ Mean: Arithmetic average of values. (AVG): SUM / N }
function Mean(const Data: array of Double): Extended;
{ Sum: Sum of values. (SUM) }
function Sum(const Data: array of Double): Extended register;
function SumInt(const Data: array of Integer): Integer register;
function SumOfSquares(const Data: array of Double): Extended;
procedure SumsAndSquares(const Data: array of Double;
var Sum, SumOfSquares: Extended) register;
{ MinValue: Returns the smallest signed value in the data array (MIN) }
function MinValue(const Data: array of Double): Double;
function MinIntValue(const Data: array of Integer): Integer;
function Min(A,B: Integer): Integer;
{$IFDEF _D4orHigher}
overload;
function Min(A,B: I64): I64; overload;
function Min(A,B: Int64): Int64; overload;
function Min(A,B: Single): Single; overload;
function Min(A,B: Double): Double; overload;
function Min(A,B: Extended): Extended; overload;
{$ENDIF}
{ MaxValue: Returns the largest signed value in the data array (MAX) }
function MaxValue(const Data: array of Double): Double;
function MaxIntValue(const Data: array of Integer): Integer;
function Max(A,B: Integer): Integer;
{$IFDEF _D4orHigher}
overload;
function Max(A,B: I64): I64; overload;
function Max(A,B: Single): Single; overload;
function Max(A,B: Double): Double; overload;
function Max(A,B: Extended): Extended; overload;
{$ENDIF}
{ Standard Deviation (STD): Sqrt(Variance). aka Sample Standard Deviation }
function StdDev(const Data: array of Double): Extended;
{ MeanAndStdDev calculates Mean and StdDev in one call. }
procedure MeanAndStdDev(const Data: array of Double; var Mean, StdDev: Extended);
{ Population Standard Deviation (STDP): Sqrt(PopnVariance).
Used in some business and financial calculations. }
function PopnStdDev(const Data: array of Double): Extended;
{ Variance (VARS): TotalVariance / (N-1). aka Sample Variance }
function Variance(const Data: array of Double): Extended;
{ Population Variance (VAR or VARP): TotalVariance/ N }
function PopnVariance(const Data: array of Double): Extended;
{ Total Variance: SUM(i=1,N)[(X(i) - Mean)**2] }
function TotalVariance(const Data: array of Double): Extended;
{ Norm: The Euclidean L2-norm. Sqrt(SumOfSquares) }
function Norm(const Data: array of Double): Extended;
{ MomentSkewKurtosis: Calculates the core factors of statistical analysis:
the first four moments plus the coefficients of skewness and kurtosis.
M1 is the Mean. M2 is the Variance.
Skew reflects symmetry of distribution: M3 / (M2**(3/2))
Kurtosis reflects flatness of distribution: M4 / Sqr(M2) }
procedure MomentSkewKurtosis(const Data: array of Double;
var M1, M2, M3, M4, Skew, Kurtosis: Extended);
{ RandG produces random numbers with Gaussian distribution about the mean.
Useful for simulating data with sampling errors. }
function RandG(Mean, StdDev: Extended): Extended;
{-----------------------------------------------------------------------
Financial functions. Standard set from Quattro Pro.
Parameter conventions:
From the point of view of A, amounts received by A are positive and
amounts disbursed by A are negative (e.g. a borrower's loan repayments
are regarded by the borrower as negative).
Interest rates are per payment period. 11% annual percentage rate on a
loan with 12 payments per year would be (11 / 100) / 12 = 0.00916667
-----------------------------------------------------------------------}
type
TPaymentTime = (ptEndOfPeriod, ptStartOfPeriod);
{ Double Declining Balance (DDB) }
function DoubleDecliningBalance(Cost, Salvage: Extended;
Life, Period: Integer): Extended;
{ Future Value (FVAL) }
function FutureValue(Rate: Extended; NPeriods: Integer; Payment, PresentValue:
Extended; PaymentTime: TPaymentTime): Extended;
{ Interest Payment (IPAYMT) }
function InterestPayment(Rate: Extended; Period, NPeriods: Integer; PresentValue,
FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
{ Interest Rate (IRATE) }
function InterestRate(NPeriods: Integer;
Payment, PresentValue, FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
{ Internal Rate of Return. (IRR) Needs array of cash flows. }
function InternalRateOfReturn(Guess: Extended;
const CashFlows: array of Double): Extended;
{ Number of Periods (NPER) }
function NumberOfPeriods(Rate, Payment, PresentValue, FutureValue: Extended;
PaymentTime: TPaymentTime): Extended;
{ Net Present Value. (NPV) Needs array of cash flows. }
function NetPresentValue(Rate: Extended; const CashFlows: array of Double;
PaymentTime: TPaymentTime): Extended;
{ Payment (PAYMT) }
function Payment(Rate: Extended; NPeriods: Integer;
PresentValue, FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
{ Period Payment (PPAYMT) }
function PeriodPayment(Rate: Extended; Period, NPeriods: Integer;
PresentValue, FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
{ Present Value (PVAL) }
function PresentValue(Rate: Extended; NPeriods: Integer;
Payment, FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
{ Straight Line depreciation (SLN) }
function SLNDepreciation(Cost, Salvage: Extended; Life: Integer): Extended;
{ Sum-of-Years-Digits depreciation (SYD) }
function SYDDepreciation(Cost, Salvage: Extended; Life, Period: Integer): Extended;
{type
EInvalidArgument = class(EMathError) end;}
{------------------------------------------------------------------------------}
{ Integer and logical functions }
function IsPowerOf2( i: Integer ): Boolean;
{* TRUE, ���� ����� �������� �������� ����� 2 }
function Low1( i: Integer ): Integer;
{* �������� ������� ��� 1 �� ����� i. }
function Low0( i: Integer ): Integer;
{* �������� ������� ������ ��� 0 �� ����� i, ��������, 1100011 -> 100 }
function count_1_bits_in_byte( x: Byte ): Byte;
{* ������������ ����� ��������� ����� � ����� }
function count_1_bits_in_dword( x: Integer ): Integer;
{* ������������ ����� ��������� ����� � 32-������ }
implementation
{$IFNDEF _D2orD3}
uses SysConst;
{$ENDIF}
function EAbs( D: Double ): Double;
begin
Result := D;
if Result < 0.0 then
Result := -Result;
end;
function EMax( const Values: array of Double ): Double;
var I: Integer;
begin
Result := Values[ 0 ];
for I := 1 to High( Values ) do
if Result < Values[ I ] then Result := Values[ I ];
end;
function EMin( const Values: array of Double ): Double;
var I: Integer;
begin
Result := Values[ 0 ];
for I := 1 to High( Values ) do
if Result > Values[ I ] then Result := Values[ I ];
end;
function ESign( X: Extended ): Integer;
begin
if X < 0 then Result := -1
else if X > 0 then Result := 1
else Result := 1;
end;
function iMax( const Values: array of Integer ): Integer;
var I: Integer;
begin
Result := Values[ 0 ];
for I := 1 to High( Values ) do
if Result < Values[ I ] then Result := Values[ I ];
end;
function iMin( const Values: array of Integer ): Integer;
var I: Integer;
begin
Result := Values[ 0 ];
for I := 1 to High( Values ) do
if Result > Values[ I ] then Result := Values[ I ];
end;
{$IFDEF PAS_VERSION}
function iSign( i: Integer ): Integer;
begin
if i < 0 then Result := -1
else if i > 0 then Result := 1
else Result := 0;
end;
{$ELSE}
function iSign( i: Integer ): Integer;
asm
XOR EDX, EDX
TEST EAX, EAX
JZ @@exit
MOV DL, 1
JG @@exit
OR EDX, -1
@@exit:
XCHG EAX, EDX
end;
{$ENDIF}
function Annuity2(R: Extended; N: Integer; PaymentTime: TPaymentTime;
var CompoundRN: Extended): Extended; Forward;
function Compound(R: Extended; N: Integer): Extended; Forward;
function RelSmall(X, Y: Extended): Boolean; Forward;
type
TPoly = record
Neg, Pos, DNeg, DPos: Extended
end;
const
MaxIterations = 15;
{$IFNDEF MATH_NOERR}
procedure ArgError(const Msg: string);
begin
raise Exception.Create(e_Math_InvalidArgument, Msg);
end;
{$ENDIF}
function DegToRad(Degrees: Extended): Extended; { Radians := Degrees * PI / 180 }
begin
Result := Degrees * (PI / 180);
end;
function RadToDeg(Radians: Extended): Extended; { Degrees := Radians * 180 / PI }
begin
Result := Radians * (180 / PI);
end;
function GradToRad(Grads: Extended): Extended; { Radians := Grads * PI / 200 }
begin
Result := Grads * (PI / 200);
end;
function RadToGrad(Radians: Extended): Extended; { Grads := Radians * 200 / PI}
begin
Result := Radians * (200 / PI);
end;
function CycleToRad(Cycles: Extended): Extended; { Radians := Cycles * 2PI }
begin
Result := Cycles * (2 * PI);
end;
function RadToCycle(Radians: Extended): Extended;{ Cycles := Radians / 2PI }
begin
Result := Radians / (2 * PI);
end;
function LnXP1(X: Extended): Extended;
{ Return ln(1 + X). Accurate for X near 0. }
asm
FLDLN2
MOV AX,WORD PTR X+8 { exponent }
FLD X
CMP AX,$3FFD { .4225 }
JB @@1
FLD1
FADD
FYL2X
JMP @@2
@@1:
FYL2XP1
@@2:
FWAIT
end;
{ Invariant: Y >= 0 & Result*X**Y = X**I. Init Y = I and Result = 1. }
{function IntPower(X: Extended; I: Integer): Extended;
var
Y: Integer;
begin
Y := Abs(I);
Result := 1.0;
while Y > 0 do begin
while not Odd(Y) do
begin
Y := Y shr 1;
X := X * X
end;
Dec(Y);
Result := Result * X
end;
if I < 0 then Result := 1.0 / Result
end;
}
(* -- already defined in kol.pas
function IntPower(Base: Extended; Exponent: Integer): Extended;
asm
mov ecx, eax
cdq
fld1 { Result := 1 }
xor eax, edx
sub eax, edx { eax := Abs(Exponent) }
jz @@3
fld Base
jmp @@2
@@1: fmul ST, ST { X := Base * Base }
@@2: shr eax,1
jnc @@1
fmul ST(1),ST { Result := Result * X }
jnz @@1
fstp st { pop X from FPU stack }
cmp ecx, 0
jge @@3
fld1
fdivrp { Result := 1 / Result }
@@3:
fwait
end;
*)
function Compound(R: Extended; N: Integer): Extended;
{ Return (1 + R)**N. }
begin
Result := IntPower(1.0 + R, N)
end;
function Annuity2(R: Extended; N: Integer; PaymentTime: TPaymentTime;
var CompoundRN: Extended): Extended;
{ Set CompoundRN to Compound(R, N),
return (1+Rate*PaymentTime)*(Compound(R,N)-1)/R;
}
begin
if R = 0.0 then
begin
CompoundRN := 1.0;
Result := N;
end
else
begin
{ 6.1E-5 approx= 2**-14 }
if EAbs(R) < 6.1E-5 then
begin
CompoundRN := Exp(N * LnXP1(R));
Result := N*(1+(N-1)*R/2);
end
else
begin
CompoundRN := Compound(R, N);
Result := (CompoundRN-1) / R
end;
if PaymentTime = ptStartOfPeriod then
Result := Result * (1 + R);
end;
end; {Annuity2}
procedure PolyX(const A: array of Double; X: Extended; var Poly: TPoly);
{ Compute A[0] + A[1]*X + ... + A[N]*X**N and X * its derivative.
Accumulate positive and negative terms separately. }
var
I: Integer;
Neg, Pos, DNeg, DPos: Extended;
begin
Neg := 0.0;
Pos := 0.0;
DNeg := 0.0;
DPos := 0.0;
for I := High(A) downto Low(A) do
begin
DNeg := X * DNeg + Neg;
Neg := Neg * X;
DPos := X * DPos + Pos;
Pos := Pos * X;
if A[I] >= 0.0 then
Pos := Pos + A[I]
else
Neg := Neg + A[I]
end;
Poly.Neg := Neg;
Poly.Pos := Pos;
Poly.DNeg := DNeg * X;
Poly.DPos := DPos * X;
end; {PolyX}
function RelSmall(X, Y: Extended): Boolean;
{ Returns True if X is small relative to Y }
const
C1: Double = 1E-15;
C2: Double = 1E-12;
begin
Result := EAbs(X) < (C1 + C2 * EAbs(Y))
end;
{ Math functions. }
function ArcCos(X: Extended): Extended;
begin
if X > 0.999999999999999 then
Result := 0 {����� -NAN !}
else
if X < -0.999999999999999 then
Result := PI
else
Result := ArcTan2(Sqrt(1 - X*X), X);
end;
function ArcSin(X: Extended): Extended;
begin
Result := ArcTan2(X, Sqrt(1 - X*X))
end;
function ArcTan2(Y, X: Extended): Extended;
asm
FLD Y
FLD X
FPATAN
FWAIT
end;
function Tan(X: Extended): Extended;
{ Tan := Sin(X) / Cos(X) }
asm
FLD X
FPTAN
FSTP ST(0) { FPTAN pushes 1.0 after result }
FWAIT
end;
function CoTan(X: Extended): Extended;
{ CoTan := Cos(X) / Sin(X) = 1 / Tan(X) }
asm
FLD X
FPTAN
FDIVRP
FWAIT
end;
function Hypot(X, Y: Extended): Extended;
{ formula: Sqrt(X*X + Y*Y)
implemented as: |Y|*Sqrt(1+Sqr(X/Y)), |X| < |Y| for greater precision
var
Temp: Extended;
begin
X := Abs(X);
Y := Abs(Y);
if X > Y then
begin
Temp := X;
X := Y;
Y := Temp;
end;
if X = 0 then
Result := Y
else // Y > X, X <> 0, so Y > 0
Result := Y * Sqrt(1 + Sqr(X/Y));
end;
}
asm
FLD Y
FABS
FLD X
FABS
FCOM
FNSTSW AX
TEST AH,$45
JNZ @@1 // if ST > ST(1) then swap
FXCH ST(1) // put larger number in ST(1)
@@1: FLDZ
FCOMP
FNSTSW AX
TEST AH,$40 // if ST = 0, return ST(1)
JZ @@2
FSTP ST // eat ST(0)
JMP @@3
@@2: FDIV ST,ST(1) // ST := ST / ST(1)
FMUL ST,ST // ST := ST * ST
FLD1
FADD // ST := ST + 1
FSQRT // ST := Sqrt(ST)
FMUL // ST(1) := ST * ST(1); Pop ST
@@3: FWAIT
end;
procedure SinCos(Theta: Extended; var Sin, Cos: Extended);
asm
FLD Theta
FSINCOS
FSTP tbyte ptr [edx] // Cos
FSTP tbyte ptr [eax] // Sin
FWAIT
end;
{ Extract exponent and mantissa from X }
procedure Frexp(X: Extended; var Mantissa: Extended; var Exponent: Integer);
{ Mantissa ptr in EAX, Exponent ptr in EDX }
asm
FLD X
PUSH EAX
MOV dword ptr [edx], 0 { if X = 0, return 0 }
FTST
FSTSW AX
FWAIT
SAHF
JZ @@Done
FXTRACT // ST(1) = exponent, (pushed) ST = fraction
FXCH
// The FXTRACT instruction normalizes the fraction 1 bit higher than
// wanted for the definition of frexp() so we need to tweak the result
// by scaling the fraction down and incrementing the exponent.
FISTP dword ptr [edx]
FLD1
FCHS
FXCH
FSCALE // scale fraction
INC dword ptr [edx] // exponent biased to match
FSTP ST(1) // discard -1, leave fraction as TOS
@@Done:
POP EAX
FSTP tbyte ptr [eax]
FWAIT
end;
function Ldexp(X: Extended; P: Integer): Extended;
{ Result := X * (2^P) }
asm
PUSH EAX
FILD dword ptr [ESP]
FLD X
FSCALE
POP EAX
FSTP ST(1)
FWAIT
end;
function Ceil(X: Extended): Integer;
begin
Result := Integer(Trunc(X));
if Frac(X) > 0 then
Inc(Result);
end;
function Floor(X: Extended): Integer;
begin
Result := Integer(Trunc(X));
if Frac(X) < 0 then
Dec(Result);
end;
{ Conversion of bases: Log.b(X) = Log.a(X) / Log.a(b) }
function Log10(X: Extended): Extended;
{ Log.10(X) := Log.2(X) * Log.10(2) }
asm
FLDLG2 { Log base ten of 2 }
FLD X
FYL2X
FWAIT
end;
function Log2(X: Extended): Extended;
asm
FLD1
FLD X
FYL2X
FWAIT
end;
function LogN(Base, X: Extended): Extended;
{ Log.N(X) := Log.2(X) / Log.2(N) }
asm
FLD1
FLD X
FYL2X
FLD1
FLD Base
FYL2X
FDIV
FWAIT
end;
function Poly(X: Extended; const Coefficients: array of Double): Extended;
{ Horner's method }
var
I: Integer;
begin
Result := Coefficients[High(Coefficients)];
for I := High(Coefficients)-1 downto Low(Coefficients) do
Result := Result * X + Coefficients[I];
end;
function Power(Base, Exponent: Extended): Extended;
begin
if Exponent = 0.0 then
Result := 1.0 { n**0 = 1 }
else if (Base = 0.0) and (Exponent > 0.0) then
Result := 0.0 { 0**n = 0, n > 0 }
else if (Frac(Exponent) = 0.0) and (EAbs(Exponent) <= MaxInt) then
Result := IntPower(Base, Integer(Trunc(Exponent)))
else
Result := Exp(Exponent * Ln(Base))
end;
{$IFNDEF _D6orHigher}
(*function Trunc1( X: Extended ): Int64;
begin
Result := System.Trunc( X );
end;
asm
FLD qword ptr [ESP+4]
{ -> FST(0) Extended argument }
{ <- EDX:EAX Result }
SUB ESP,12
FNSTCW [ESP].Word // save
FNSTCW [ESP+2].Word // scratch
FWAIT
OR [ESP+2].Word, $0F00 // trunc toward zero, full precision
FLDCW [ESP+2].Word
FISTP qword ptr [ESP+4]
FWAIT
FLDCW [ESP].Word
POP ECX
POP EAX
POP EDX
end;*)
function Trunc( X: Extended ): Int64;
begin
if Abs( X ) < 1 then Result := 0 else
if X < 0 then Result := -System.Trunc( -X )
else Result := System.Trunc( X );
end;
{$ENDIF}
{ Hyperbolic functions }
function CoshSinh(X: Extended; Factor: Double): Extended;
begin
Result := Exp(X) / 2;
Result := Result + Factor / Result;
end;
function Cosh(X: Extended): Extended;
begin
Result := CoshSinh(X, 0.25)
end;
function Sinh(X: Extended): Extended;
begin
Result := CoshSinh(X, -0.25)
end;
const
MaxTanhDomain = 5678.22249441322; // Ln(MaxExtended)/2
function Tanh(X: Extended): Extended;
begin
if X > MaxTanhDomain then
Result := 1.0
else if X < -MaxTanhDomain then
Result := -1.0
else
begin
Result := Exp(X);
Result := Result * Result;
Result := (Result - 1.0) / (Result + 1.0)
end;
end;
function ArcCosh(X: Extended): Extended;
begin
if X <= 1.0 then
Result := 0.0
else if X > 1.0e10 then
Result := Ln(2) + Ln(X)
else
Result := Ln(X + Sqrt((X - 1.0) * (X + 1.0)));
end;
function ArcSinh(X: Extended): Extended;
var
Neg: Boolean;
begin
if X = 0 then
Result := 0
else
begin
Neg := (X < 0);
X := EAbs(X);
if X > 1.0e10 then
Result := Ln(2) + Ln(X)
else
begin
Result := X*X;
Result := LnXP1(X + Result / (1 + Sqrt(1 + Result)));
end;
if Neg then Result := -Result;
end;
end;
function ArcTanh(X: Extended): Extended;
var
Neg: Boolean;
begin
if X = 0 then
Result := 0
else
begin
Neg := (X < 0);
X := EAbs(X);
if X >= 1 then
Result := MaxExtended
else
Result := 0.5 * LnXP1((2.0 * X) / (1.0 - X));
if Neg then Result := -Result;
end;
end;
{ Statistical functions }
function Mean(const Data: array of Double): Extended;
begin
Result := SUM(Data) / (High(Data) - Low(Data) + 1)
end;
function MinValue(const Data: array of Double): Double;
var
I: Integer;
begin
Result := Data[Low(Data)];
for I := Low(Data) + 1 to High(Data) do
if Result > Data[I] then
Result := Data[I];
end;
function MinIntValue(const Data: array of Integer): Integer;
var
I: Integer;
begin
Result := Data[Low(Data)];
for I := Low(Data) + 1 to High(Data) do
if Result > Data[I] then
Result := Data[I];
end;
{$IFDEF ASM_VERSION}
function Min(A,B: Integer): Integer;
asm
CMP EAX, EDX
JL @@1
XCHG EAX, EDX
@@1:
end;
{$ELSE}
function Min(A,B: Integer): Integer;
begin
if A < B then
Result := A
else
Result := B;
end;
{$ENDIF}
{$IFDEF _D4orHigher}
function Min(A,B: I64): I64;
begin
if Cmp64( A, B ) < 0 then
Result := A
else
Result := B;
end;
function Min(A,B: Int64): Int64;
begin
if A < B then
Result := A
else
Result := B;
end;
function Min(A,B: Single): Single;
begin
if A < B then
Result := A
else
Result := B;
end;
function Min(A,B: Double): Double;
begin
if A < B then
Result := A
else
Result := B;
end;
function Min(A,B: Extended): Extended;
begin
if A < B then
Result := A
else
Result := B;
end;
{$ENDIF}
function MaxValue(const Data: array of Double): Double;
var
I: Integer;
begin
Result := Data[Low(Data)];
for I := Low(Data) + 1 to High(Data) do
if Result < Data[I] then
Result := Data[I];
end;
function MaxIntValue(const Data: array of Integer): Integer;
var
I: Integer;
begin
Result := Data[Low(Data)];
for I := Low(Data) + 1 to High(Data) do
if Result < Data[I] then
Result := Data[I];
end;
{$IFDEF ASM_VERSION}
function Max(A,B: Integer): Integer;
asm
CMP EAX, EDX
JG @@1
XCHG EAX, EDX
@@1:
end;
{$ELSE}
function Max(A,B: Integer): Integer;
begin
if A > B then
Result := A
else
Result := B;
end;
{$ENDIF}
{$IFDEF _D4orHigher}
function Max(A,B: I64): I64;
begin
if Cmp64( A, B ) > 0 then
Result := A
else
Result := B;
end;
function Max(A,B: Single): Single;
begin
if A > B then
Result := A
else
Result := B;
end;
function Max(A,B: Double): Double;
begin
if A > B then
Result := A
else
Result := B;
end;
function Max(A,B: Extended): Extended;
begin
if A > B then
Result := A
else
Result := B;
end;
{$ENDIF}
procedure MeanAndStdDev(const Data: array of Double; var Mean, StdDev: Extended);
var
S: Extended;
N,I: Integer;
begin
N := High(Data)- Low(Data) + 1;
if N = 1 then
begin
Mean := Data[0];
StdDev := Data[0];
Exit;
end;
Mean := Sum(Data) / N;
S := 0; // sum differences from the mean, for greater accuracy
for I := Low(Data) to High(Data) do
S := S + Sqr(Mean - Data[I]);
StdDev := Sqrt(S / (N - 1));
end;
procedure MomentSkewKurtosis(const Data: array of Double;
var M1, M2, M3, M4, Skew, Kurtosis: Extended);
var
Sum, SumSquares, SumCubes, SumQuads, OverN, Accum, M1Sqr, S2N, S3N: Extended;
I: Integer;
begin
OverN := 1 / (High(Data) - Low(Data) + 1);
Sum := 0;
SumSquares := 0;
SumCubes := 0;
SumQuads := 0;
for I := Low(Data) to High(Data) do
begin
Sum := Sum + Data[I];
Accum := Sqr(Data[I]);
SumSquares := SumSquares + Accum;
Accum := Accum*Data[I];
SumCubes := SumCubes + Accum;
SumQuads := SumQuads + Accum*Data[I];
end;
M1 := Sum * OverN;
M1Sqr := Sqr(M1);
S2N := SumSquares * OverN;
S3N := SumCubes * OverN;
M2 := S2N - M1Sqr;
M3 := S3N - (M1 * 3 * S2N) + 2*M1Sqr*M1;
M4 := (SumQuads * OverN) - (M1 * 4 * S3N) + (M1Sqr*6*S2N - 3*Sqr(M1Sqr));
Skew := M3 * Power(M2, -3/2); // = M3 / Power(M2, 3/2)
Kurtosis := M4 / Sqr(M2);
end;
function Norm(const Data: array of Double): Extended;
begin
Result := Sqrt(SumOfSquares(Data));
end;
function PopnStdDev(const Data: array of Double): Extended;
begin
Result := Sqrt(PopnVariance(Data))
end;
function PopnVariance(const Data: array of Double): Extended;
begin
Result := TotalVariance(Data) / (High(Data) - Low(Data) + 1)
end;
function RandG(Mean, StdDev: Extended): Extended;
{ Marsaglia-Bray algorithm }
var
U1, S2: Extended;
begin
repeat
U1 := 2*Random - 1;
S2 := Sqr(U1) + Sqr(2*Random-1);
until S2 < 1;
Result := Sqrt(-2*Ln(S2)/S2) * U1 * StdDev + Mean;
end;
function StdDev(const Data: array of Double): Extended;
begin
Result := Sqrt(Variance(Data))
end;
procedure RaiseOverflowError; forward;
function SumInt(const Data: array of Integer): Integer;
{var
I: Integer;
begin
Result := 0;
for I := Low(Data) to High(Data) do
Result := Result + Data[I]
end; }
asm // IN: EAX = ptr to Data, EDX = High(Data) = Count - 1
// loop unrolled 4 times, 5 clocks per loop, 1.2 clocks per datum
PUSH EBX
MOV ECX, EAX // ecx = ptr to data
MOV EBX, EDX
XOR EAX, EAX
AND EDX, not 3
AND EBX, 3
SHL EDX, 2
JMP @Vector.Pointer[EBX*4]
@Vector:
DD @@1
DD @@2
DD @@3
DD @@4
@@4:
ADD EAX, [ECX+12+EDX]
JO @@RaiseOverflowError
@@3:
ADD EAX, [ECX+8+EDX]
JO @@RaiseOverflowError
@@2:
ADD EAX, [ECX+4+EDX]
JO @@RaiseOverflowError
@@1:
ADD EAX, [ECX+EDX]
JO @@RaiseOverflowError
SUB EDX,16
JNS @@4
POP EBX
RET
@@RaiseOverflowError:
POP EBX
POP ECX
JMP RaiseOverflowError
end;
procedure RaiseOverflowError;
begin
{$IFNDEF MATH_NOERR}
raise Exception.Create(e_IntOverflow, SIntOverflow);
{$ENDIF}
end;
function SUM(const Data: array of Double): Extended;
{var
I: Integer;
begin
Result := 0.0;
for I := Low(Data) to High(Data) do
Result := Result + Data[I]
end; }
asm // IN: EAX = ptr to Data, EDX = High(Data) = Count - 1
// Uses 4 accumulators to minimize read-after-write delays and loop overhead
// 5 clocks per loop, 4 items per loop = 1.2 clocks per item
FLDZ
MOV ECX, EDX
FLD ST(0)
AND EDX, not 3
FLD ST(0)
AND ECX, 3
FLD ST(0)
SHL EDX, 3 // count * sizeof(Double) = count * 8
JMP @Vector.Pointer[ECX*4]
@Vector:
DD @@1
DD @@2
DD @@3
DD @@4
@@4: FADD qword ptr [EAX+EDX+24] // 1
FXCH ST(3) // 0
@@3: FADD qword ptr [EAX+EDX+16] // 1
FXCH ST(2) // 0
@@2: FADD qword ptr [EAX+EDX+8] // 1
FXCH ST(1) // 0
@@1: FADD qword ptr [EAX+EDX] // 1
FXCH ST(2) // 0
SUB EDX, 32
JNS @@4
FADDP ST(3),ST // ST(3) := ST + ST(3); Pop ST
FADD // ST(1) := ST + ST(1); Pop ST
FADD // ST(1) := ST + ST(1); Pop ST
FWAIT
end;
function SumOfSquares(const Data: array of Double): Extended;
var
I: Integer;
begin
Result := 0.0;
for I := Low(Data) to High(Data) do
Result := Result + Sqr(Data[I]);
end;
procedure SumsAndSquares(const Data: array of Double; var Sum, SumOfSquares: Extended);
{var
I: Integer;
begin
Sum := 0;
SumOfSquares := 0;
for I := Low(Data) to High(Data) do
begin
Sum := Sum + Data[I];
SumOfSquares := SumOfSquares + Data[I]*Data[I];
end;
end; }
asm // IN: EAX = ptr to Data
// EDX = High(Data) = Count - 1
// ECX = ptr to Sum
// Est. 17 clocks per loop, 4 items per loop = 4.5 clocks per data item
FLDZ // init Sum accumulator
PUSH ECX
MOV ECX, EDX
FLD ST(0) // init Sqr1 accum.
AND EDX, not 3
FLD ST(0) // init Sqr2 accum.
AND ECX, 3
FLD ST(0) // init/simulate last data item left in ST
SHL EDX, 3 // count * sizeof(Double) = count * 8
JMP @Vector.Pointer[ECX*4]
@Vector:
DD @@1
DD @@2
DD @@3
DD @@4
@@4: FADD // Sqr2 := Sqr2 + Sqr(Data4); Pop Data4
FLD qword ptr [EAX+EDX+24] // Load Data1
FADD ST(3),ST // Sum := Sum + Data1
FMUL ST,ST // Data1 := Sqr(Data1)
@@3: FLD qword ptr [EAX+EDX+16] // Load Data2
FADD ST(4),ST // Sum := Sum + Data2
FMUL ST,ST // Data2 := Sqr(Data2)
FXCH // Move Sqr(Data1) into ST(0)
FADDP ST(3),ST // Sqr1 := Sqr1 + Sqr(Data1); Pop Data1
@@2: FLD qword ptr [EAX+EDX+8] // Load Data3
FADD ST(4),ST // Sum := Sum + Data3
FMUL ST,ST // Data3 := Sqr(Data3)
FXCH // Move Sqr(Data2) into ST(0)
FADDP ST(3),ST // Sqr1 := Sqr1 + Sqr(Data2); Pop Data2
@@1: FLD qword ptr [EAX+EDX] // Load Data4
FADD ST(4),ST // Sum := Sum + Data4
FMUL ST,ST // Sqr(Data4)
FXCH // Move Sqr(Data3) into ST(0)
FADDP ST(3),ST // Sqr1 := Sqr1 + Sqr(Data3); Pop Data3
SUB EDX,32
JNS @@4
FADD // Sqr2 := Sqr2 + Sqr(Data4); Pop Data4
POP ECX
FADD // Sqr1 := Sqr2 + Sqr1; Pop Sqr2
FXCH // Move Sum1 into ST(0)
MOV EAX, SumOfSquares
FSTP tbyte ptr [ECX] // Sum := Sum1; Pop Sum1
FSTP tbyte ptr [EAX] // SumOfSquares := Sum1; Pop Sum1
FWAIT
end;
function TotalVariance(const Data: array of Double): Extended;
var
Sum, SumSquares: Extended;
begin
SumsAndSquares(Data, Sum, SumSquares);
Result := SumSquares - Sqr(Sum)/(High(Data) - Low(Data) + 1);
end;
function Variance(const Data: array of Double): Extended;
begin
Result := TotalVariance(Data) / (High(Data) - Low(Data))
end;
{ Depreciation functions. }
function DoubleDecliningBalance(Cost, Salvage: Extended; Life, Period: Integer): Extended;
{ dv := cost * (1 - 2/life)**(period - 1)
DDB = (2/life) * dv
if DDB > dv - salvage then DDB := dv - salvage
if DDB < 0 then DDB := 0
}
var
DepreciatedVal, Factor: Extended;
begin
Result := 0;
if (Period < 1) or (Life < Period) or (Life < 1) or (Cost <= Salvage) then
Exit;
{depreciate everything in period 1 if life is only one or two periods}
if ( Life <= 2 ) then
begin
if ( Period = 1 ) then
DoubleDecliningBalance:=Cost-Salvage
else
DoubleDecliningBalance:=0; {all depreciation occurred in first period}
exit;
end;
Factor := 2.0 / Life;
DepreciatedVal := Cost * IntPower((1.0 - Factor), Period - 1);
{DepreciatedVal is Cost-(sum of previous depreciation results)}
Result := Factor * DepreciatedVal;
{Nominal computed depreciation for this period. The rest of the
function applies limits to this nominal value. }
{Only depreciate until total depreciation equals cost-salvage.}
if Result > DepreciatedVal - Salvage then
Result := DepreciatedVal - Salvage;
{No more depreciation after salvage value is reached. This is mostly a nit.
If Result is negative at this point, it's very close to zero.}
if Result < 0.0 then
Result := 0.0;
end;
function SLNDepreciation(Cost, Salvage: Extended; Life: Integer): Extended;
{ Spreads depreciation linearly over life. }
begin
{$IFNDEF MATH_NOERR}
if Life < 1 then ArgError('SLNDepreciation');
{$ENDIF}
Result := (Cost - Salvage) / Life
end;
function SYDDepreciation(Cost, Salvage: Extended; Life, Period: Integer): Extended;
{ SYD = (cost - salvage) * (life - period + 1) / (life*(life + 1)/2) }
{ Note: life*(life+1)/2 = 1+2+3+...+life "sum of years"
The depreciation factor varies from life/sum_of_years in first period = 1
downto 1/sum_of_years in last period = life.
Total depreciation over life is cost-salvage.}
var
X1, X2: Extended;
begin
Result := 0;
if (Period < 1) or (Life < Period) or (Cost <= Salvage) then Exit;
X1 := 2 * (Life - Period + 1);
X2 := Life * (Life + 1);
Result := (Cost - Salvage) * X1 / X2
end;
{ Discounted cash flow functions. }
function InternalRateOfReturn(Guess: Extended; const CashFlows: array of Double): Extended;
{
Use Newton's method to solve NPV = 0, where NPV is a polynomial in
x = 1/(1+rate). Split the coefficients into negative and postive sets:
neg + pos = 0, so pos = -neg, so -neg/pos = 1
Then solve:
log(-neg/pos) = 0
Let t = log(1/(1+r) = -LnXP1(r)
then r = exp(-t) - 1
Iterate on t, then use the last equation to compute r.
}
var
T, Y: Extended;
Poly: TPoly;
K, Count: Integer;
function ConditionP(const CashFlows: array of Double): Integer;
{ Guarantees existence and uniqueness of root. The sign of payments
must change exactly once, the net payout must be always > 0 for
first portion, then each payment must be >= 0.
Returns: 0 if condition not satisfied, > 0 if condition satisfied
and this is the index of the first value considered a payback. }
var
X: Double;
I, K: Integer;
begin
K := High(CashFlows);
while (K >= 0) and (CashFlows[K] >= 0.0) do Dec(K);
Inc(K);
if K > 0 then
begin
X := 0.0;
I := 0;
while I < K do begin
X := X + CashFlows[I];
if X >= 0.0 then
begin
K := 0;
Break
end;
Inc(I)
end
end;
ConditionP := K
end;
begin
InternalRateOfReturn := 0;
K := ConditionP(CashFlows);
{$IFNDEF MATH_NOERR}
if K < 0 then ArgError('InternalRateOfReturn');
{$ENDIF}
if K = 0 then
begin
{$IFNDEF MATH_NOERR}
if Guess <= -1.0 then ArgError('InternalRateOfReturn');
{$ENDIF}
T := -LnXP1(Guess)
end else
T := 0.0;
for Count := 1 to MaxIterations do
begin
PolyX(CashFlows, Exp(T), Poly);
{$IFNDEF MATH_NOERR}
if Poly.Pos <= Poly.Neg then ArgError('InternalRateOfReturn');
{$ENDIF}
if (Poly.Neg >= 0.0) or (Poly.Pos <= 0.0) then
begin
InternalRateOfReturn := -1.0;
Exit;
end;
with Poly do
Y := Ln(-Neg / Pos) / (DNeg / Neg - DPos / Pos);
T := T - Y;
if RelSmall(Y, T) then
begin
InternalRateOfReturn := Exp(-T) - 1.0;
Exit;
end
end;
{$IFNDEF MATH_NOERR}
ArgError('InternalRateOfReturn');
{$ENDIF}
end;
function NetPresentValue(Rate: Extended; const CashFlows: array of Double;
PaymentTime: TPaymentTime): Extended;
{ Caution: The sign of NPV is reversed from what would be expected for standard
cash flows!}
var
rr: Extended;
I: Integer;
begin
{$IFNDEF MATH_NOERR}
if Rate <= -1.0 then ArgError('NetPresentValue');
{$ENDIF}
rr := 1/(1+Rate);
result := 0;
for I := High(CashFlows) downto Low(CashFlows) do
result := rr * result + CashFlows[I];
if PaymentTime = ptEndOfPeriod then result := rr * result;
end;
{ Annuity functions. }
{---------------
From the point of view of A, amounts received by A are positive and
amounts disbursed by A are negative (e.g. a borrower's loan repayments
are regarded by the borrower as negative).
Given interest rate r, number of periods n:
compound(r, n) = (1 + r)**n "Compounding growth factor"
annuity(r, n) = (compound(r, n)-1) / r "Annuity growth factor"
Given future value fv, periodic payment pmt, present value pv and type
of payment (start, 1 , or end of period, 0) pmtTime, financial variables satisfy:
fv = -pmt*(1 + r*pmtTime)*annuity(r, n) - pv*compound(r, n)
For fv, pv, pmt:
C := compound(r, n)
A := (1 + r*pmtTime)*annuity(r, n)
Compute both at once in Annuity2.
if C > 1E16 then A = C/r, so:
fv := meaningless
pv := -pmt*(pmtTime+1/r)
pmt := -pv*r/(1 + r*pmtTime)
else
fv := -pmt(1+r*pmtTime)*A - pv*C
pv := (-pmt(1+r*pmtTime)*A - fv)/C
pmt := (-pv*C-fv)/((1+r*pmtTime)*A)
---------------}
function PaymentParts(Period, NPeriods: Integer; Rate, PresentValue,
FutureValue: Extended; PaymentTime: TPaymentTime; var IntPmt: Extended):
Extended;
var
Crn:extended; { =Compound(Rate,NPeriods) }
Crp:extended; { =Compound(Rate,Period-1) }
Arn:extended; { =AnnuityF(Rate,NPeriods) }
begin
{$IFNDEF MATH_NOERR}
if Rate <= -1.0 then ArgError('PaymentParts');
{$ENDIF}
Crp:=Compound(Rate,Period-1);
Arn:=Annuity2(Rate,NPeriods,PaymentTime,Crn);
IntPmt:=(FutureValue*(Crp-1)-PresentValue*(Crn-Crp))/Arn;
PaymentParts:=(-FutureValue-PresentValue)*Crp/Arn;
end;
function FutureValue(Rate: Extended; NPeriods: Integer; Payment, PresentValue:
Extended; PaymentTime: TPaymentTime): Extended;
var
Annuity, CompoundRN: Extended;
begin
{$IFNDEF MATH_NOERR}
if Rate <= -1.0 then ArgError('FutureValue');
{$ENDIF}
Annuity := Annuity2(Rate, NPeriods, PaymentTime, CompoundRN);
{$IFNDEF MATH_NOERR}
if CompoundRN > 1.0E16 then ArgError('FutureValue');
{$ENDIF}
FutureValue := -Payment * Annuity - PresentValue * CompoundRN
end;
function InterestPayment(Rate: Extended; Period, NPeriods: Integer; PresentValue,
FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
var
Crp:extended; { compound(rate,period-1)}
Crn:extended; { compound(rate,nperiods)}
Arn:extended; { annuityf(rate,nperiods)}
begin
{$IFNDEF MATH_NOERR}
if (Rate <= -1.0)
or (Period < 1) or (Period > NPeriods) then ArgError('InterestPayment');
{$ENDIF}
Crp:=Compound(Rate,Period-1);
Arn:=Annuity2(Rate,Nperiods,PaymentTime,Crn);
InterestPayment:=(FutureValue*(Crp-1)-PresentValue*(Crn-Crp))/Arn;
end;
function InterestRate(NPeriods: Integer;
Payment, PresentValue, FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
{
Given:
First and last payments are non-zero and of opposite signs.
Number of periods N >= 2.
Convert data into cash flow of first, N-1 payments, last with
first < 0, payment > 0, last > 0.
Compute the IRR of this cash flow:
0 = first + pmt*x + pmt*x**2 + ... + pmt*x**(N-1) + last*x**N
where x = 1/(1 + rate).
Substitute x = exp(t) and apply Newton's method to
f(t) = log(pmt*x + ... + last*x**N) / -first
which has a unique root given the above hypotheses.
}
var
X, Y, Z, First, Pmt, Last, T, ET, EnT, ET1: Extended;
Count: Integer;
Reverse: Boolean;
function LostPrecision(X: Extended): Boolean;
asm
XOR EAX, EAX
MOV BX,WORD PTR X+8
INC EAX
AND EBX, $7FF0
JZ @@1
CMP EBX, $7FF0
JE @@1
XOR EAX,EAX
@@1:
end;
begin
Result := 0;
{$IFNDEF MATH_NOERR}
if NPeriods <= 0 then ArgError('InterestRate');
{$ENDIF}
Pmt := Payment;
if PaymentTime = ptEndOfPeriod then
begin
X := PresentValue;
Y := FutureValue + Payment
end
else
begin
X := PresentValue + Payment;
Y := FutureValue
end;
First := X;
Last := Y;
Reverse := False;
if First * Payment > 0.0 then
begin
Reverse := True;
T := First;
First := Last;
Last := T
end;
if first > 0.0 then
begin
First := -First;
Pmt := -Pmt;
Last := -Last
end;
{$IFNDEF MATH_NOERR}
if (First = 0.0) or (Last < 0.0) then ArgError('InterestRate');
{$ENDIF}
T := 0.0; { Guess at solution }
for Count := 1 to MaxIterations do
begin
EnT := Exp(NPeriods * T);
if {LostPrecision(EnT)} ent=(ent+1) then
begin
Result := -Pmt / First;
if Reverse then
Result := Exp(-LnXP1(Result)) - 1.0;
Exit;
end;
ET := Exp(T);
ET1 := ET - 1.0;
if ET1 = 0.0 then
begin
X := NPeriods;
Y := X * (X - 1.0) / 2.0
end
else
begin
X := ET * (Exp((NPeriods - 1) * T)-1.0) / ET1;
Y := (NPeriods * EnT - ET - X * ET) / ET1
end;
Z := Pmt * X + Last * EnT;
Y := Ln(Z / -First) / ((Pmt * Y + Last * NPeriods *EnT) / Z);
T := T - Y;
if RelSmall(Y, T) then
begin
if not Reverse then T := -T;
InterestRate := Exp(T)-1.0;
Exit;
end
end;
{$IFNDEF MATH_NOERR}
ArgError('InterestRate');
{$ENDIF}
end;
function NumberOfPeriods(Rate, Payment, PresentValue, FutureValue: Extended;
PaymentTime: TPaymentTime): Extended;
{ If Rate = 0 then nper := -(pv + fv) / pmt
else cf := pv + pmt * (1 + rate*pmtTime) / rate
nper := LnXP1(-(pv + fv) / cf) / LnXP1(rate) }
var
PVRPP: Extended; { =PV*Rate+Payment } {"initial cash flow"}
T: Extended;
begin
{$IFNDEF MATH_NOERR}
if Rate <= -1.0 then ArgError('NumberOfPeriods');
{$ENDIF}
{whenever both Payment and PaymentTime are given together, the PaymentTime has the effect
of modifying the effective Payment by the interest accrued on the Payment}
if ( PaymentTime=ptStartOfPeriod ) then
Payment:=Payment*(1+Rate);
{if the payment exactly matches the interest accrued periodically on the
presentvalue, then an infinite number of payments are going to be
required to effect a change from presentvalue to futurevalue. The
following catches that specific error where payment is exactly equal,
but opposite in sign to the interest on the present value. If PVRPP
("initial cash flow") is simply close to zero, the computation will
be numerically unstable, but not as likely to cause an error.}
PVRPP:=PresentValue*Rate+Payment;
{$IFNDEF MATH_NOERR}
if PVRPP=0 then ArgError('NumberOfPeriods');
{$ENDIF}
{ 6.1E-5 approx= 2**-14 }
if ( EAbs(Rate)<6.1E-5 ) then
Result:=-(PresentValue+FutureValue)/PVRPP
else
begin
{starting with the initial cash flow, each compounding period cash flow
should result in the current value approaching the final value. The
following test combines a number of simultaneous conditions to ensure
reasonableness of the cashflow before computing the NPER.}
T:= -(PresentValue+FutureValue)*Rate/PVRPP;
{$IFNDEF MATH_NOERR}
if T<=-1.0 then ArgError('NumberOfPeriods');
{$ENDIF}
Result := LnXP1(T) / LnXP1(Rate)
end;
NumberOfPeriods:=Result;
end;
function Payment(Rate: Extended; NPeriods: Integer; PresentValue, FutureValue:
Extended; PaymentTime: TPaymentTime): Extended;
var
Annuity, CompoundRN: Extended;
begin
{$IFNDEF MATH_NOERR}
if Rate <= -1.0 then ArgError('Payment');
{$ENDIF}
Annuity := Annuity2(Rate, NPeriods, PaymentTime, CompoundRN);
if CompoundRN > 1.0E16 then
Payment := -PresentValue * Rate / (1 + Integer(PaymentTime) * Rate)
else
Payment := (-PresentValue * CompoundRN - FutureValue) / Annuity
end;
function PeriodPayment(Rate: Extended; Period, NPeriods: Integer;
PresentValue, FutureValue: Extended; PaymentTime: TPaymentTime): Extended;
var
Junk: Extended;
begin
{$IFNDEF MATH_NOERR}
if (Rate <= -1.0) or (Period < 1) or (Period > NPeriods) then ArgError('PeriodPayment');
{$ENDIF}
PeriodPayment := PaymentParts(Period, NPeriods, Rate, PresentValue,
FutureValue, PaymentTime, Junk);
end;
function PresentValue(Rate: Extended; NPeriods: Integer; Payment, FutureValue:
Extended; PaymentTime: TPaymentTime): Extended;
var
Annuity, CompoundRN: Extended;
begin
{$IFNDEF MATH_NOERR}
if Rate <= -1.0 then ArgError('PresentValue');
{$ENDIF}
Annuity := Annuity2(Rate, NPeriods, PaymentTime, CompoundRN);
if CompoundRN > 1.0E16 then
PresentValue := -(Payment / Rate * Integer(PaymentTime) * Payment)
else
PresentValue := (-Payment * Annuity - FutureValue) / CompoundRN
end;
{------------------------------------------------------------------------------}
function IsPowerOf2( i: Integer ): Boolean; { Result = (i <> 0) and (i and (i-1) = 0); }
asm
OR EAX,EAX
JZ @@exit // 0 �� �������� �������� ����� 2
LEA EDX, [EAX-1]
OR EAX,EDX
SETZ AL // ����� �������� �������� 2, ���� (i & (i-1)) = 0, �.�. ���� �����
// ��������� ������� 1 � ����� ������ �� �������� ����� 1.
@@exit:
end;
function Low1( i: Integer ): Integer; { Result := i and (-i); }
asm
MOV EDX, EAX
NEG EAX
AND EAX, EDX
end;
function Low0( i: Integer ): Integer; { Result := -i and (i+1); }
asm
LEA EDX, [EAX+1]
NEG EAX
AND EAX, EDX
end;
function count_1_bits_in_byte( x: Byte ): Byte;
asm
MOV CL, AL
@@loop:
SHR CL, 1
JZ @@exit
SUB AL, CL
JMP @@loop
@@exit:
end;
function count_1_bits_in_dword( x: Integer ): Integer;
asm
MOV ECX, EAX
JMP @@go
@@loop:
SUB EAX, ECX
@@go:
SHR ECX, 1
JNZ @@loop
end;
end.