# Reference:Math.inc

This file contains many general math functions and macros.

#### Float functions and macros

`even(N)`

: A function to test whether N is even, returns 1 when true, 0 when false.

Parameters:

`N`

= Input value

`odd(N)`

: A function to test whether N is odd, returns 1 when true, 0 when false.

Parameters:

`N`

= Input value

`Interpolate(GC, GS, GE, TS, TE, Method)`

: Interpolation macro, interpolates between the float values `TS`

and `TE`

. The method of interpolation is cosine, linear or exponential. The position where to evaluate the interpolation is determined by the position of `GC`

in the range `GS`

- `GE`

. See the example below.

Parameters:

`GC`

= global current, float value within the range GS - GE`GS`

= global start`GE`

= global end`TS`

= target start`TE`

= target end`Method`

= interpolation method, float value:`Method`

< 0 : exponential, using the value of Method as exponent.`Method`

= 0 : cosine interpolation.`Method`

> 0 : exponential, using the value of Method as exponent.`Method`

= 1 : linear interpolation,

Example:

#declare A = Interpolate(0.5, 0, 1, 0, 10, 1); #debug str(A,0,2) // result A = 5.00 #declare A = Interpolate(0.0,-2, 2, 0, 10, 1); #debug str(A,0,2) // result A = 5.00 #declare A = Interpolate(0.5, 0, 1, 0, 10, 2); #debug str(A,0,2) // result A = 2.50

`Mean(A)`

: A macro to compute the average of an array of values.

Parameters:

`A`

= An array of float or vector values.

`Std_Dev(A, M)`

: A macro to compute the standard deviation.

Parameters:

`A`

= An array of float values.`M`

= Mean of the floats in the array.

`GetStats(A)`

: This macro declares a global array named `StatisticsArray`

containing: N, Mean, Min, Max, and Standard Deviation

Parameters:

`A`

= An array of float values.

`Histogram(ValArr, Intervals)`

: This macro declares a global, 2D array named `HistogramArray`

. The first value in the array is the center of the interval/bin, the second the number of values in that interval.

Parameters:

`ValArr`

= An array with values.`Intervals`

= The desired number of intervals/bins.

`sind(v), cosd(v), tand(v), asind(v), acosd(v), atand(v), atan2d(a, b)`

: These functions are versions of the
trigonometric functions using degrees, instead of radians, as the angle unit.

Parameters:

- The same as for the analogous built-in trig function.

`max3(a, b, c)`

: A function to find the largest of three numbers.

Parameters:

`a, b, c`

= Input values.

`min3(a, b, c)`

: A function to find the smallest of three numbers.

Parameters:

`a, b, c`

= Input values.

`f_sqr(v)`

: A function to square a number.

Parameters:

`v`

= Input value.

`sgn(v)`

: A function to show the sign of the number. Returns -1 or 1 depending on the sign of v.

Parameters:

`v`

= Input value.

`clip(V, Min, Max)`

: A function that limits a value to a specific range, if it goes outside that range it is *clipped*. Input values larger than `Max`

will return `Max`

, those less than `Min`

will return `Min`

.

Parameters:

`V`

= Input value.`Min`

= Minimum of output range.`Max`

= Maximum of output range.

`clamp(V, Min, Max)`

: A function that limits a value to a specific range, if it goes outside that range it is *clamped* to this range, wrapping around. As the input increases or decreases outside the given range, the output will
repeatedly sweep through that range, making a *sawtooth* waveform.

Parameters:

`V`

= Input value.`Min`

= Minimum of output range.`Max`

= Maximum of output range.

`adj_range(V, Min, Max)`

: A function that adjusts input values in the range [0, 1] to a given range. An input value of 0 will return `Min`

, 1 will return `Max`

, and values outside the [0, 1] range will be linearly extrapolated (the graph will continue in a straight line).

Parameters:

`V`

= Input value.`Min`

= Minimum of output range.`Max`

= Maximum of output range.

`adj_range2(V, InMin, InMax, OutMin, OutMax)`

: Like `adj_range()`

, but adjusts input values in the range `[InMin, InMax]`

to the range `[OutMin, OutMax]`

.

Parameters:

`V`

= Input value.`InMin`

= Minimum of input range.`InMax`

= Maximum of input range.`OutMin`

= Minimum of output range.`OutMax`

= Maximum of output range.

#### Vector functions and macros

These are all macros in the current version because functions can not take vector parameters, but this may change in the future.

`VSqr(V)`

: Square each individual component of a vector, equivalent to `V*V`

.

Parameters:

`V`

= Vector to be squared.

`VPow(V, P), VPow5D(V, P)`

: Raise each individual component of a vector to a given power.

Parameters:

`V`

= Input vector.`P`

= Power.

`VEq(V1, V2)`

: Tests for equal vectors, returns true if all three components of `V1`

equal the respective components of `V2`

.

Parameters:

`V1, V2`

= The vectors to be compared.

`VEq5D(V1, V2)`

: A 5D version of `VEq()`

. Tests for equal vectors, returns true if all 5 components of `V1 `

equal the respective components of `V2`

.

Parameters:

`V1, V2`

= The vectors to be compared.

`VZero(V)`

: Tests for a < 0, 0, 0> vector.

Parameters:

`V`

= Input vector.

`VZero5D(V)`

: Tests for a < 0, 0, 0, 0, 0> vector.

Parameters:

`V`

= Input vector.

`VLength5D(V)`

: Computes the length of a 5D vector.

Parameters:

`V`

= Input vector.

`VNormalize5D(V)`

: Normalizes a 5D vector.

Parameters:

`V`

= Input vector.

`VDot5D(V1, V2)`

: Computes the dot product of two 5D vectors. See vdot() for more information on dot products.

Parameters:

`V`

= Input vector.

`VCos_Angle(V1, V2)`

: Compute the cosine of the angle between two vectors.

Parameters:

`V1, V2`

= Input vectors.

`VAngle(V1, V2), VAngleD(V1, V2)`

: Compute the angle between two vectors. `VAngle()`

returns the angle in radians, `VAngleD()`

in degrees.

Parameters:

`V1, V2`

= Input vectors.

`VRotation(V1, V2, Axis)`

and `VRotationD(V1, V2, Axis)`

: Compute the rotation angle from V1 to V2 around Axis. Axis should be perpendicular to both V1 and V2. The output will be in the range between -pi and pi radians or between -180 degrees and 180 degrees if you are using the degree version. However, if Axis is set to <0,0,0> the output will always be positive or zero, the same result you will get with the VAngle() macros.

Parameters:

`V1, V2`

= Input vectors.

`VDist(V1, V2)`

: Compute the distance between two points.

Parameters:

`V1, V2`

= Input vectors.

`VPerp_To_Vector(V)`

: Find a vector perpendicular to the given vector.

Parameters:

`V`

= Input vector.

`VPerp_To_Plane(V1, V2)`

: Find a vector perpendicular to both given vectors. In other words, perpendicular to the plane defined by the two input vectors.

Parameters:

`V1, V2`

= Input vectors.

`VPerp_Adjust(V1, Axis)`

: Find a vector perpendicular to Axis and in the plane of V1 and Axis. In other words, the new vector is a version of V1 adjusted to be perpendicular to Axis.

Parameters:

`V1, Axis`

= Input vectors.

`VProject_Plane(V1, Axis)`

: Project vector V1 onto the plane defined by Axis.

Parameters:

`V1`

= Input vectors.`Axis`

= Normal of the plane.

`VProject_Axis(V1, Axis)`

: Project vector V1 onto the axis defined by Axis.

Parameters:

`V1, Axis`

= Input vectors.

`VMin(V), VMax(V)`

: Find the smallest or largest component of a vector.

Parameters:

`V`

= Input vector.

`VWith_Len(V, Len)`

: Create a vector parallel to a given vector but with a given length.

Parameters:

`V`

= Direction vector.`Len`

= Length of desired vector.

#### Vector Analysis

`SetGradientAccuracy(Value)`

: All the macros below make use of a constant named *__Gradient_Fn_Accuracy_* for numerical approximation of the derivatives. This constant can be changed with the macro, the default value is 0.001.

`fn_Gradient(Fn)`

: A macro calculating the gradient of a function as a function.

Parameters:

`Fn`

= function to calculate the gradient from.

Output: the length of the gradient as a function.

`fn_Gradient_Directional(Fn, Dir)`

: A macro calculating the gradient of a function in one direction as a function.

Parameters:

`Fn`

= function to calculate the gradient from.`Dir`

= direction to calculate the gradient.

Output: the gradient in that direction as a function.

`fn_Divergence(Fnx, Fny, Fnz)`

: A macro calculating the divergence of a (vector) function as a function.

Parameters:

`Fnx, Fny, Fnz`

= x, y and z components of a vector function.

Output: the divergence as a function.

`vGradient(Fn, p0)`

: A macro calculating the gradient of a function as a vector expression.

Parameters:

`Fn`

= function to calculate the gradient from.`p0`

= point where to calculate the gradient.

Output: the gradient as a vector expression.

`vCurl(Fnx, Fny, Fnz, p0)`

: A macro calculating the curl of a (vector) function as a vector expression.

Parameters:

`Fnx, Fny, Fnz`

= x, y and z components of a vector function.`p0`

= point where to calculate the gradient.

Output: the curl as a vector expression

`Divergence(Fnx, Fny, Fnz, p0)`

: A macro calculating the divergence of a (vector) function as a float expression.

Parameters:

`Fnx, Fny, Fnz`

= x, y and z components of a vector function.`p0`

= point where to calculate the gradient.

Output: the divergence as a float expression.

`Gradient_Length(Fn, p0)`

: A macro calculating the length of the gradient of a function as a float expression.

Parameters:

`Fn`

= function to calculate the gradient from.`p0`

= point where to calculate the gradient.

Output: the length of the gradient as a float expression.

`Gradient_Directional(Fn, p0, Dir)`

: A macro calculating the gradient of a function in one direction as a float expression.

Parameters:

`Fn`

= function to calculate the gradient from.`p0`

= point where to calculate the gradient.`Dir`

= direction to calculate the gradient.

Output: the gradient in that direction as a float expression