Math Class Reference

#include <e32math.h>

class Math
Public Member Functions
IMPORT_C TIntACos(TReal &, const TReal &)
IMPORT_C TIntASin(TReal &, const TReal &)
IMPORT_C TIntATan(TReal &, const TReal &)
IMPORT_C TIntATan(TReal &, const TReal &, const TReal &)
IMPORT_C TIntCos(TReal &, const TReal &)
IMPORT_C Int64DivMod64(Int64, Int64, Int64 &)
IMPORT_C TIntExp(TReal &, const TReal &)
IMPORT_C TRealFRand(TInt64 &)
IMPORT_C TIntFrac(TReal &, const TReal &)
IMPORT_C TIntInt(TReal &, const TReal &)
IMPORT_C TIntInt(TInt16 &, const TReal &)
IMPORT_C TIntInt(TInt32 &, const TReal &)
IMPORT_C TBoolIsFinite(const TReal &)
IMPORT_C TBoolIsInfinite(const TReal &)
IMPORT_C TBoolIsNaN(const TReal &)
IMPORT_C TBoolIsZero(const TReal &)
IMPORT_C TIntLn(TReal &, const TReal &)
IMPORT_C TIntLog(TReal &, const TReal &)
IMPORT_C TIntMod(TReal &, const TReal &, const TReal &)
IMPORT_C voidMul64(Int64, Int64, Int64 &, Uint64 &)
TInt MultPow10X(TRealX &, TInt)
IMPORT_C TRealPoly(TReal, const SPoly *)
IMPORT_C voidPolyX(TRealX &, const TRealX &, TInt, const TRealX *)
IMPORT_C TIntPow(TReal &, const TReal &, const TReal &)
IMPORT_C TIntPow10(TReal &, const TInt)
IMPORT_C TIntRand(TInt64 &)
IMPORT_C TUint32Random()
IMPORT_C voidRandom(TDes8 &)
IMPORT_C voidRandomL(TDes8 &)
IMPORT_C TUint32RandomL()
IMPORT_C TIntRound(TReal &, const TReal &, TInt)
IMPORT_C TIntSin(TReal &, const TReal &)
IMPORT_C TIntSqrt(TReal &, const TReal &)
IMPORT_C TIntTan(TReal &, const TReal &)
IMPORT_C Uint64UDivMod64(Uint64, Uint64, Uint64 &)
IMPORT_C voidUMul64(Uint64, Uint64, Uint64 &, Uint64 &)

Detailed Description

A collection of mathematical functions.

Member Function Documentation

ACos ( TReal &, const TReal & )

IMPORT_C TIntACos(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the principal value of the inverse cosine of a number.

Parameters
aTrgA reference containing the result in radians, a value between 0 and pi.
aSrcThe argument of the arccos function, a value between -1 and +1 inclusive.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

ASin ( TReal &, const TReal & )

IMPORT_C TIntASin(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the principal value of the inverse sine of a number.

Parameters
aTrgA reference containing the result in radians, a value between -pi/2 and +pi/2.
aSrcThe argument of the arcsin function, a value between -1 and +1 inclusive.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

ATan ( TReal &, const TReal & )

IMPORT_C TIntATan(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the principal value of the inverse tangent of a number.

Parameters
aTrgA reference containing the result in radians, a value between -pi/2 and +pi/2.
aSrcThe argument of the arctan function, a value between +infinity and +infinity.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

ATan ( TReal &, const TReal &, const TReal & )

IMPORT_C TIntATan(TReal &aTrg,
const TReal &aSrcY,
const TReal &aSrcX
)[static]

Calculates the angle between the x-axis and a line drawn from the origin to a point represented by its (x,y) co-ordinates.

The co-ordinates are passed as arguments to the function. This function returns the same result as arctan(y/x), but:

1. it adds +/-pi to the result, if x is negative

2. it sets the result to +/-pi/2, if x is zero but y is non-zero.

Parameters
aTrgA reference containing the result in radians, a value between -pi exclusive and +pi inclusive.
aSrcYThe y argument of the arctan(y/x) function.
aSrcXThe x argument of the arctan(y/x) function.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Cos ( TReal &, const TReal & )

IMPORT_C TIntCos(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the cosine of a number.

Parameters
aTrgA reference containing the result.
aSrcThe argument of the cos function in radians
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

DivMod64 ( Int64, Int64, Int64 & )

IMPORT_C Int64DivMod64(Int64aDividend,
Int64aDivisor,
Int64 &aRemainder
)[static]

Divides aDividend by aDivisor.

The quotient is returned, and the remainder is stored in aRemainder. The remainder has same sign as the dividend.

Parameters
aDividendThe 64-bit dividend.
aDivisorThe 64-bit divisor.
aRemainderThe 64-bit remainder.
Return Value
The 64-bit quotient.

Exp ( TReal &, const TReal & )

IMPORT_C TIntExp(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the value of e to the power of x.

Parameters
aTrgA reference containing the result.
aSrcThe power to which e is to be raised.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

FRand ( TInt64 & )

IMPORT_C TRealFRand(TInt64 &aSeed)[static]

Generates a stream of uniformly distributed pseudo-random real numbers in the range, 0 to 1.

Parameters
aSeedA reference to a 64-bit seed, which is updated as a result of the call.
Return Value
The next pseudo-random number in the sequence.

Frac ( TReal &, const TReal & )

IMPORT_C TIntFrac(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the fractional part of a number.

The fractional part is that after a decimal point. Truncation is toward zero, so that Frac(2.4)=0.4, Frac(2)=0, Frac(-1)=0, Frac(-1.4)=0.4.

Parameters
aTrgA reference containing the result.
aSrcThe number whose fractional part is required.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Int ( TReal &, const TReal & )

IMPORT_C TIntInt(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the integer part of a number.

The integer part is that before a decimal point. Truncation is toward zero, so that int(2.4)=2, int(2)=2, int(-1)=-1, int(-1.4)=-1, int(-1.999)=-1.

Parameters
aTrgA reference containing the result.
aSrcThe number whose integer part is required.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Int ( TInt16 &, const TReal & )

IMPORT_C TIntInt(TInt16 &aTrg,
const TReal &aSrc
)[static]

Calculates the integer part of a number.

The integer part is that before a decimal point. Truncation is toward zero, so that int(2.4)=2, int(2)=2, int(-1)=-1, int(-1.4)=-1, int(-1.999)=-1.

This function is suitable when the result is known to be small enough for a 16-bit signed integer.

Parameters
aTrgA reference containing the result.
aSrcThe number whose integer part is required.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Int ( TInt32 &, const TReal & )

IMPORT_C TIntInt(TInt32 &aTrg,
const TReal &aSrc
)[static]

Calculates the integer part of a number.

The integer part is that before a decimal point. Truncation is toward zero, so that int(2.4)=2, int(2)=2, int(-1)=-1, int(-1.4)=-1, int(-1.999)=-1.

This function is suitable when the result is known to be small enough for a 32-bit signed integer.

Parameters
aTrgA reference containing the result.
aSrcThe number whose integer part is required.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

IsFinite ( const TReal & )

IMPORT_C TBoolIsFinite(const TReal &aVal)[static]

Determines whether a value is finite.

In this context, a value is finite if it is a valid number and is not infinite.

Parameters
aValA reference to the value to be checked.
Return Value
True, if aVal is finite; false, otherwise.

IsInfinite ( const TReal & )

IMPORT_C TBoolIsInfinite(const TReal &aVal)[static]

Determines whether a value is infinite.

Parameters
aValA reference to the value to be checked.
Return Value
True, if aVal is infinite; false, otherwise.

IsNaN ( const TReal & )

IMPORT_C TBoolIsNaN(const TReal &aVal)[static]

Determines whether a value is not a number.

Parameters
aValA reference to the value to be checked.
Return Value
True, if aVal is not a number; false, otherwise.

IsZero ( const TReal & )

IMPORT_C TBoolIsZero(const TReal &aVal)[static]

Determines whether a value is zero.

Parameters
aValA reference to the value to be checked.
Return Value
True, if aVal is zero; false, otherwise.

Ln ( TReal &, const TReal & )

IMPORT_C TIntLn(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the natural logarithm of a number.

Parameters
aTrgA reference containing the result.
aSrcThe number whose natural logarithm is required.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Log ( TReal &, const TReal & )

IMPORT_C TIntLog(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the logarithm to base 10 of a number.

Parameters
aTrgA reference containing the result.
aSrcThe number whose logarithm is required.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Mod ( TReal &, const TReal &, const TReal & )

IMPORT_C TIntMod(TReal &aTrg,
const TReal &aSrc,
const TReal &aModulus
)[static]

Calculates the modulo remainder.

This is the value of p mod q, the modulo remainder when dividing p by q. The result is given by p - q int (p/q): it has the same sign as p: thus, 5 mod 3 = 2, -5 mod 3 = -2. No error is raised if non-integer arguments are passed.

Parameters
aTrgA reference containing the result.
aSrcThe p argument to the mod function.
aModulusThe q argument to the mod function.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Mul64 ( Int64, Int64, Int64 &, Uint64 & )

IMPORT_C voidMul64(Int64aX,
Int64aY,
Int64 &aOutH,
Uint64 &aOutL
)[static]

Multiply aX by aY to generate a 128 bit result.

The high order 64 bits of this calculation are stored in aOutH, and the low order 64 bits are stored in aOutL.

Parameters
aXThe first 64-bit operand.
aYThe second 64-bit operand.
aOutHThe high order 64 bits of the result.
aOutLThe low order 64 bits of the result.

MultPow10X ( TRealX &, TInt )

TInt MultPow10X(TRealX &aTrg,
TIntaPower
)[static]

Poly ( TReal, const SPoly * )

IMPORT_C TRealPoly(TRealaVal,
const SPoly *aPoly
)[static]

Evaluates the polynomial: {a[n]X^n + a[n-1]X^(n-1) + ... + a[2]X^2 + a[1]X^1 + a[0]}.

Parameters
aValThe value of the x-variable
aPolyA pointer to the structure containing the set of coefficients in the order: a[0], a[1], ..., a[n-1], a[n].
Return Value
The result of the evaluation.

PolyX ( TRealX &, const TRealX &, TInt, const TRealX * )

IMPORT_C voidPolyX(TRealX &aY,
const TRealX &aX,
TIntaDeg,
const TRealX *aCoef
)[static]

Evaluates the polynomial: {a[n]X^n + a[n-1]X^(n-1) + ... + a[2]X^2 + a[1]X^1 + a[0]}.

Parameters
aYA reference containing the result.
aXThe value of the x-variable.
aDegThe degree of the polynomial (the highest power of x which is present).
aCoefA pointer to a contiguous set of TRealX values containing the coefficients. They must be in the order: a[0], a[1], ..., a[n-1], a[n].

Pow ( TReal &, const TReal &, const TReal & )

IMPORT_C TIntPow(TReal &aTrg,
const TReal &aSrc,
const TReal &aPower
)[static]

Calculates the value of x raised to the power of y.

The behaviour conforms to that specified for pow() in the ISO C Standard ISO/IEC 9899 (Annex F), although floating-point exceptions are not supported.

Parameters
aTrgA reference containing the result.
aSrcThe x argument of the function.
aPowerThe y argument of the function.
Return Value
KErrNone if successful; KErrOverflow if the result is +/- infinity; KErrUnderflow if the result is too small to be represented; KErrArgument if the result is not a number (NaN).

Pow10 ( TReal &, const TInt )

IMPORT_C TIntPow10(TReal &aTrg,
const TIntexp
)[static]

Calculates the value of 10 to the power of x.

Parameters
aTrgA reference containing the result.
expThe power to which 10 is to be raised.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Rand ( TInt64 & )

IMPORT_C TIntRand(TInt64 &aSeed)[static]

Generates a stream of uniformly distributed pseudo-random integers in the range, 0 to KMaxTInt.

For each stream of pseudo-random numbers you wish to generate, you should pass the reference to the same 64-bit seed on each call to this function. You should not change the seed between calls.

Parameters
aSeedA reference to a 64-bit seed, which is updated as a result of the call.
Return Value
The next pseudo-random number in the sequence.

Random ( )

IMPORT_C TUint32Random()[static]

Gets 32 random bits from the kernel's random number generator.

The returned random data may or may not be cryptographically secure but should be of a high quality for non-cryptographic purposes.

This function uses a cryptographically strong random number generator to generate the random data, which can be slower than insecure generators. If security is not important, a faster generator may be used such as Math::Rand().

Return Value
The 32 random bits.

Random ( TDes8 & )

IMPORT_C voidRandom(TDes8 &aRandomValue)[static]

Fills the provided descriptor with random data up to its current length. The number of random bytes required should be specified by setting the length of the descriptor that is passed to this function.

The returned random data may or may not be cryptographically secure but should be of a high quality for non-cryptographic purposes.

This function uses a cryptographically strong random number generator to generate the random data, which can be slower than insecure generators. If security is not important, a faster generator may be used such as Math::Rand().

Parameters
aRandomValueon return, the descriptor is filled with the requested number of random bytes.

RandomL ( TDes8 & )

IMPORT_C voidRandomL(TDes8 &aRandomValue)[static]

Fills the provided descriptor with random data up to its current length. The number of random bytes required should be specified by setting the length of the descriptor that is passed to the function.

If the returned random data cannot be guaranteed to be cryptographically secure, the function will leave with KErrNotReady to indicate that the returned data should not be used for cryptographic purposes.

The security strength of the cryptographically strong random number generator is 256 bits.

Parameters
aRandomValueon return, the descriptor is filled with the requested number of random bytes.
Leave Codes
KErrNotReadyif the returned random data cannot be guaranteed to be cryptographically secure.

RandomL ( )

IMPORT_C TUint32RandomL()[static]

Gets 32 random bits from the kernel's random number generator.

If the returned random data could not be guaranteed to be cryptographically secure, the function will instead leave with KErrNotReady to indicate that data was not available.

The security strength of the cryptographically strong random number generator is 256 bits.

Return Value
The 32 random bits.
Leave Codes
KErrNotReadyif no data was returned as it could not be guaranteed to be cryptographically secure.

Round ( TReal &, const TReal &, TInt )

IMPORT_C TIntRound(TReal &aTrg,
const TReal &aSrc,
TIntaDecimalPlaces
)[static]

Rounds to a specified number of decimal places.

The function rounds a number to a given number, n, of decimal places. Rounding may be thought of as multiplying the number by 10 to the power of n, rounding to the nearest integer, and then dividing the result by 10 to the power of n and returning that as the answer.

In the process of rounding, numbers ending with .5 are rounded away from zero, so that 1.5 becomes 2, 2.5 becomes 3, -1.5 becomes -2, etc.

Parameters
aTrgA reference containing the result.
aSrcThe number to be rounded.
aDecimalPlacesThe number of decimal places to round to: must be zero or positive.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Sin ( TReal &, const TReal & )

IMPORT_C TIntSin(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the sine of a number.

Parameters
aTrgA reference containing the result.
aSrcThe argument of the sin function in radians.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Sqrt ( TReal &, const TReal & )

IMPORT_C TIntSqrt(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the square root of a number.

Parameters
aTrgA reference containing the result.
aSrcThe number whose square-root is required.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

Tan ( TReal &, const TReal & )

IMPORT_C TIntTan(TReal &aTrg,
const TReal &aSrc
)[static]

Calculates the tangent of a number.

Parameters
aTrgA reference containing the result.
aSrcThe argument of the tan function in radians.
Return Value
KErrNone if successful, otherwise another of the system-wide error codes.

UDivMod64 ( Uint64, Uint64, Uint64 & )

IMPORT_C Uint64UDivMod64(Uint64aDividend,
Uint64aDivisor,
Uint64 &aRemainder
)[static]

Divides aDividend by aDivisor.

The quotient is returned, and the remainder is stored in aRemainder.

Parameters
aDividendThe 64-bit dividend.
aDivisorThe 64-bit divisor.
aRemainderThe 64-bit remainder.
Return Value
The 64-bit quotient.

UMul64 ( Uint64, Uint64, Uint64 &, Uint64 & )

IMPORT_C voidUMul64(Uint64aX,
Uint64aY,
Uint64 &aOutH,
Uint64 &aOutL
)[static]

Multiply aX by aY to generate a 128 bit result.

The high order 64 bits of this calculation are stored in aOutH, and the low order 64 bits are stored in aOutL.

Parameters
aXThe first 64-bit operand.
aYThe second 64-bit operand.
aOutHThe high order 64 bits of the result.
aOutLThe low order 64 bits of the result.