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[stdlib_math] add arg/argd/argpi #498

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Merged
merged 8 commits into from
Dec 19, 2021
Merged

[stdlib_math] add arg/argd/argpi #498

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286ddf6
add `arg/argd/argpi` for `stdlib_math`
zoziha Aug 28, 2021
feca677
Tighter tests for `arg/argd/argpi`.
zoziha Sep 19, 2021
733a3e5
Merge branch 'master' into add_arg
zoziha Dec 10, 2021
6e00619
Update `test-drive` style tests for arg* routines.
zoziha Dec 10, 2021
ec04eca
Remove old tests for arg* routines.
zoziha Dec 10, 2021
c37c0b2
arg**: `aimag(log(..)) -> atan2(..)`,
zoziha Dec 14, 2021
b382db9
Merge branch 'master' into add_arg
zoziha Dec 19, 2021
7e1e4fa
Update CHANGELOG.md
zoziha Dec 19, 2021
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Tighter tests for arg/argd/argpi.
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@zoziha
zoziha committed Sep 19, 2021
commit feca677eba8d88a2c5a14b020878330c6672380c
6 changes: 3 additions & 3 deletions doc/specs/stdlib_math.md
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Expand Up @@ -356,7 +356,7 @@ Elemental function.

### Description

`arg` computes the phase angle (radian version) of `complex` scalar in the interval [-π,π].
`arg` computes the phase angle (radian version) of `complex` scalar in the interval (-π,π].
The angles in `theta` are such that `z = abs(z)*exp((0.0, theta))`.

### Syntax
Expand Down Expand Up @@ -399,7 +399,7 @@ Elemental function.

### Description

`argd` computes the phase angle (degree version) of `complex` scalar in the interval [-180.0,180.0].
`argd` computes the phase angle (degree version) of `complex` scalar in the interval (-180.0,180.0].
The angles in `theta` are such that `z = abs(z)*exp((0.0, theta*π/180.0))`.

### Syntax
Expand Down Expand Up @@ -442,7 +442,7 @@ Elemental function.

### Description

`argpi` computes the phase angle (circular version) of `complex` scalar in the interval [-1.0,1.0].
`argpi` computes the phase angle (circular version) of `complex` scalar in the interval (-1.0,1.0].
The angles in `theta` are such that `z = abs(z)*exp((0.0, theta*π))`.

### Syntax
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36 changes: 23 additions & 13 deletions src/tests/math/test_math_arg.f90
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@@ -1,6 +1,6 @@
program tester

real :: tol = 1.0e-3
real :: tol = epsilon(1.0)
call test_math_arg_complex
call test_math_argd_complex
call test_math_argpi_complex
Expand All @@ -9,32 +9,42 @@ program tester
contains

subroutine test_math_arg_complex
use stdlib_math, only: arg
use stdlib_math, only: arg
use stdlib_error, only: check

call check(abs(arg(2.0*exp((0.0e0, 0.5))) - 0.5) < tol, msg="arg(2.0*exp((0.0, 0.5))) failed.")
call check(abs(arg((1.7552, 0.9589)) - 0.5) < tol, msg="arg((1.7552, 0.9589)) failed.")
call check(abs(arg((0.0, 0.0)) - 0.0) < tol, msg="arg((0.0, 0.0)) failed.")
print *, 2.0*exp((0.0e0, 0.5)) !! (1.75516510, 0.958851099)

call check(abs(arg(2.0*exp((0.0e0, 0.5))) - 0.5) < tol, msg="arg(2.0*exp((0.0e0, 0.5))) - 0.5) failed.")
call check(abs(arg((1.75516510, 0.958851099)) - 0.5) < tol, msg="arg((1.75516510, 0.958851099)) - 0.5) failed.")
call check(abs(arg((0.0, 0.0)) - 0.0) < tol, msg="arg((0.0, 0.0)) failed.")

end subroutine test_math_arg_complex

subroutine test_math_argd_complex
use stdlib_math, only: argd
use stdlib_math, only: argd
use stdlib_error, only: check

call check(abs(argd(2.0*exp((0.0, 0.5))) - 28.648) < tol, msg="argd(2.0*exp((0.0, 0.5))) failed.")
call check(abs(argd((1.7552, 0.9589)) - 28.648) < tol, msg="argd((1.7552, 0.9589)) failed.")
call check(abs(argd((0.0, 0.0)) - 0.0) < tol, msg="argd((0.0, 0.0)) failed.")
call check(abs(argd(2.0*exp((0.0, 0.5))) - 28.6478882) < tol, msg="argd(2.0*exp((0.0, 0.5))) - 28.6478882) failed.")
call check(abs(argd((1.75516510, 0.958851099)) - 28.6478882) < tol, &
msg="argd((1.75516510, 0.958851099)) - 28.6478882) failed.")
call check(abs(argd((0.0, 0.0)) - 0.0) < tol, msg="argd((0.0, 0.0)) failed.")

end subroutine test_math_argd_complex

subroutine test_math_argpi_complex
use stdlib_math, only: argpi
use stdlib_math, only: argpi
use stdlib_error, only: check
real, parameter :: PI = 4*atan(1.0)

!> Power exponent calculation will introduce calculation errors: 2.0*exp((0.0, PI)) /= (-2.0, 0.0).
print *, 2.0*exp((0.0, PI)), 2.0*exp(cmplx(0.0, -PI)) !! (-2.00000000,-1.748455531E-07), (-2.00000000,1.748455531E-07)
print *, argpi(2.0*exp((0.0, PI))), argpi(2.0*exp(cmplx(0.0, -PI))) !! -0.999999940, 0.999999940

call check(abs(argpi(2.0*exp((0.0, PI))) - (- 1.0)) < tol, msg="argpi(2.0*exp((0.0, PI))) - (- 1.0)) failed.")
call check(abs(argpi(2.0*exp(cmplx(0.0, -PI))) - 1.0) < tol, msg="argpi(2.0*exp(cmplx(0.0, -PI))) - 1.0) failed.")

call check(abs(argpi(2.0*exp((0.0, 0.5))) - 0.159) < tol, msg="argpi(2.0*exp((0.0, 0.5))) failed.")
call check(abs(argpi((1.7552, 0.9589)) - 0.159) < tol, msg="argpi((1.7552, 0.9589)) failed.")
call check(abs(argpi((0.0, 0.0)) - 0.0) < tol, msg="argpi((0.0, 0.0)) failed.")
call check(abs(argpi((-2.0, 0.0)) - 1.0) < tol, msg="argpi((-2.0, 0.0)) - 1.0) failed.") !! (-1.0, 1.0]
call check(abs(argpi(( 0.0, 0.0)) - 0.0) < tol, msg="argpi((0.0, 0.0)) failed.")

end subroutine test_math_argpi_complex

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