# acospi (Core Functions) 1.x.x.x

### Import

#include <archr/core/acospi.h>
#include <archr/core/acospi.hpp>
import archr.core

### Synopsis

 float archr_core_acospi_1f32(const float i1); (1) double archr_core_acospi_1f64(const double i1); (2) void archr_core_acospi_f32(float *o0, const float *i1, size_t sz); (3) void archr_core_acospi_f64(double *o0, const double *i1, size_t sz); (4)
 float acospi(const float i1); (1) double acospi(const double i1); (2) void acospi(const float *i1, size_t sz, float *o0); (3) void acospi(const double *i1, size_t sz, double *o0); (4) template void acospi(const Range& i1, Range& o0); (5)
 subroutine archr_core_acospi_1f32(real(4) :: r, real(4), parameter :: i1) (1) subroutine archr_core_acospi_1f64(real(8) :: r, real(8), parameter :: i1) (2) subroutine archr_core_acospi_f32(real(4), dimension(*), parameter :: i1, integer(4) :: sz, real(4), dimension(*) :: o0) (3) subroutine archr_core_acospi_f64(real(8), dimension(*), parameter :: i1, integer(4) :: sz, real(8), dimension(*) :: o0) (4)
 def acospi(i1): return o0 (1)
 function o0 = archr_core_acospi(i1) (1)

### Description

Computes the Inverse Cosine in multiple of PIs:

• to the range defined by:

• [i1_first, i1_last)
• [i1, i1 + sz)

and stores the result in another range, beginning at o0.

• of its i1ument and returns it.

### Parameters

 i1_first, i1_last The range of input elements o0 The beginning of the destination range, may be equal to i1 i1 The scalar/contiguous data input element

### Example

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stddef.h>
#include <archr/core/acospi.h>

double rand_in(double min, double max) {
return min + ((double)(max - min) * ((double)rand() / RAND_MAX));
}

int main() {
time_t t;
size_t i;
size_t sz = 10;
float* i1 = (float*)malloc(sz * sizeof(float));
float* o1 = (float*)malloc(sz * sizeof(float));

srand((unsigned int)time(&t));
for (i = 0; i < sz; ++i) {
i1[i] = (float)rand_in((float)-1, (float)1);
}
archr_core_acospi_f32(o1, i1, sz);
for (i = 0; i < sz; ++i) {
printf("%4lu: acospi(%f) = %f\n", i, (double)i1[i], (double)o1[i]);
}
}

### Possible Output

0: acospi(0.942286) = 0.108672
1: acospi(0.183788) = 0.441164
2: acospi(-0.326225) = 0.605777
3: acospi(-0.782217) = 0.785911
4: acospi(-0.500638) = 0.666901
5: acospi(-0.805106) = 0.797892
6: acospi(0.494578) = 0.335322
7: acospi(0.934714) = 0.115655
8: acospi(0.510651) = 0.329404
9: acospi(0.634508) = 0.281203

#include <ctime>
#include <cstdio>
#include <cstdlib>
#include <cstdint>
#include <cstddef>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <archr/core/acospi.hpp>

double rand_in(double min, double max) {
return min + (double(max - min) * (double(std::rand()) / RAND_MAX));
}

int main() {
std::size_t i;
std::size_t sz = 10;
std::vector<float> i1(sz);
std::vector<float> o1(sz);

std::srand(std::time(0));
std::generate(i1.begin(), i1.end(), []() { return rand_in(float(-1), float(1)); });
archr::core::acospi(i1.data(), sz, o1.data());
for (i = 0; i < sz; ++i) {
std::cout << std::setw(4) << i << ": " << "acospi" << "(" << i1[i] << ")" << " = " << o1[i] << std::endl;
}
}

### Possible Output

0: acospi(-0.782005) = 0.785803
1: acospi(-0.65429) = 0.727032
2: acospi(-0.937116) = 0.886515
3: acospi(0.569177) = 0.307262
4: acospi(0.616947) = 0.288369
5: acospi(0.746037) = 0.231954
6: acospi(-0.236809) = 0.576102
7: acospi(-0.672507) = 0.734783
8: acospi(0.89037) = 0.150446
9: acospi(-0.545268) = 0.683572

program main
integer(4), parameter  :: sz = 10
real(4), dimension(sz) :: o0
real(4), dimension(sz) :: i0
real(8)                :: r0, r1
real(8)                :: min0, max0
real(8)                :: min1, max1
real(8)                :: min2, max2
! Init:
min0 = -1
max0 = 1
do i=1,sz
r0 = random_in(min0, max0)
i0(i) = r0
end do
! Example:
call archr_core_acospi_f32(o0, i0, size(i0))
! Output:
do i=1,sz
print *, i, ": ", o0(i)
end do
contains
! Generate a random number within a range
function random_in(mn, mx) result(r)
real(8) :: r
real(8), intent(in) :: mn, mx
r = mn + (rand() * (mx - mn))
end function random_in
end program

### Possible Output

1 :   0.998241544
2 :   0.763722718
3 :   0.329197258
4 :   0.526354253
5 :   0.479124874
6 :   0.689999402
7 :   0.860812485
8 :   0.383551151
9 :   0.383256763
10 :   0.164514750