test: add tests for negative values in math/base/special/fmod

PR-URL: #2600
Ref: 8558d86#commitcomment-144215763
Reviewed-by: Athan Reines <kgryte@gmail.com>
Signed-off-by: GUNJ JOSHI <gunjjoshi8372@gmail.com>

Author: gunjjoshi

lib/node_modules/@stdlib/math/base/special/fmod/README.md

@@ -169,6 +169,7 @@ double stdlib_base_fmod( const double x, const double y );
 
 ```c
 #include "stdlib/math/base/special/fmod.h"
+#include <stdlib.h>
 #include <stdio.h>
 
 int main( void ) {

lib/node_modules/@stdlib/math/base/special/fmod/src/main.c

@@ -46,7 +46,7 @@
 *
 * @param x    dividend
 * @param y    divisor
-* @returns    remainder
+* @return    remainder
 *
 * @example
 * double out = stdlib_base_fmod( 8.9, 3.0 );
@@ -86,14 +86,14 @@ double stdlib_base_fmod( const double x, const double y ) {
 	// Purge off exception values
 	if ( ( hy | ly ) == 0 || ( hx >= STDLIB_CONSTANT_FLOAT64_HIGH_WORD_EXPONENT_MASK ) || ( ( hy | ( ( ly | -ly ) >> 31 ) ) > STDLIB_CONSTANT_FLOAT64_HIGH_WORD_EXPONENT_MASK ) ) {
 		// y=0, x not finite, or y is NaN
-	    return ( x * y ) / ( x * y );
+		return ( x * y ) / ( x * y );
 	}
 	if ( hx <= hy ) {
-	    if ( ( hx < hy ) || ( lx < ly ) ){
+		if ( ( hx < hy ) || ( lx < ly ) ){
 			// |x|<|y| return x
 			return x;
 		}
-	    if ( lx == ly ) {
+		if ( lx == ly ) {
 			// |x|=|y| return x*0
 			return ZERO[ (uint32_t)sx >> 31 ];
 		}
@@ -102,86 +102,84 @@ double stdlib_base_fmod( const double x, const double y ) {
 	// Determine ix = ilogb(x)
 	if ( hx < 0x00100000 ) {
 		// subnormal x
-	    if ( hx == 0 ) {
+		if ( hx == 0 ) {
 			ix = -1043;
 			for ( i = lx; i > 0; i <<= 1 ) {
 				ix -=1;
 			}
-	    } else {
+		} else {
 			ix = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT;
 			for ( i = ( hx << 11 ); i > 0; i <<= 1 ) {
 				ix -=1;
 			}
-	    }
+		}
 	} else {
 		ix = ( hx >> 20 ) - STDLIB_CONSTANT_FLOAT64_EXPONENT_BIAS;
 	}
 
-    // determine iy = ilogb(y)
+	// determine iy = ilogb(y)
 	if ( hy < 0x00100000 ) {
 		// subnormal y
-	    if ( hy == 0 ) {
+		if ( hy == 0 ) {
 			iy = -1043;
 			for ( i = ly; i > 0; i <<= 1 ) {
 				iy -=1;
 			}
-	    } else {
+		} else {
 			iy = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT;
 			for ( i = ( hy << 11 ); i > 0; i <<= 1) {
 				iy -=1;
 			}
-	    }
+		}
 	} else {
 		iy = ( hy >> 20 ) - STDLIB_CONSTANT_FLOAT64_EXPONENT_BIAS;
 	}
 
-    // set up {hx,lx}, {hy,ly} and align y to x
+	// set up {hx,lx}, {hy,ly} and align y to x
 	if ( ix >= STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT ) {
 		hx = 0x00100000 | ( STDLIB_CONSTANT_FLOAT64_HIGH_WORD_SIGNIFICAND_MASK & hx );
-	}
-	else {
+	} else {
 		// subnormal x, shift x to normal
-	    n = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT - ix;
-	    if ( n <= 31 ) {
-	        hx = ( (uint32_t)hx << n ) | ( lx >> ( 32 - n ) );
-	        lx <<= n;
+		n = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT - ix;
+		if ( n <= 31 ) {
+			hx = ( (uint32_t)hx << n ) | ( lx >> ( 32 - n ) );
+			lx <<= n;
 	    } else {
 			hx = lx << ( n - 32 );
 			lx = 0;
-	    }
+		}
 	}
 	if ( iy >= STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT ) {
 		hy = 0x00100000 | ( STDLIB_CONSTANT_FLOAT64_HIGH_WORD_SIGNIFICAND_MASK & hy );
-	}
-	else {
+	} else {
 		// subnormal y, shift y to normal
-	    n = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT - iy;
-	    if ( n <= 31 ) {
-	        hy = ( (uint32_t)hy << n ) | ( ly >> ( 32 - n ) );
-	        ly <<= n;
-	    } else {
+		n = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT - iy;
+		if ( n <= 31 ) {
+			hy = ( (uint32_t)hy << n ) | ( ly >> ( 32 - n ) );
+			ly <<= n;
+		} else {
 			hy = ly << ( n - 32 );
 			ly = 0;
-	    }
+		}
 	}
 	n = ix - iy;
 	while ( n-- ) {
-	    hz = hx - hy;
+		hz = hx - hy;
 		lz = lx - ly;
 		if ( lx < ly ) {
 			hz -= 1;
 		}
-	    if ( hz < 0 ) {
+		if ( hz < 0 ) {
 			hx = hx + hx + ( lx >> 31 );
 			lx += lx;
-		}
-	    else {
-	    	if ( ( hz | lz ) == 0 )
-			// return sign(x)*0
-		    return ZERO[ (uint32_t)sx >> 31 ];
-	    	hx = hz + hz + ( lz >> 31 );
+		} else {
+			if ( ( hz | lz ) == 0 ) {
+				// return sign(x)*0
+				return ZERO[ (uint32_t)sx >> 31 ];
+			}
+			hx = hz + hz + ( lz >> 31 );
 			lx = lz + lz;
-	    }
+		}
 	}
 	hz = hx - hy;
 	lz = lx - ly;
@@ -193,34 +191,34 @@ double stdlib_base_fmod( const double x, const double y ) {
 		lx = lz;
 	}
 
-    // Convert back to floating value and restore the sign
+	// Convert back to floating value and restore the sign
 	if ( ( hx | lx ) == 0 ) {
 		// return sign(x)*0
 		return ZERO[ (uint32_t)sx >> 31 ];
 	}
 	while ( hx < 0x00100000 ) {
 		// normalize x
-	    hx = hx + hx + ( lx >> 31 );
+		hx = hx + hx + ( lx >> 31 );
 		lx += lx;
-	    iy -= 1;
+		iy -= 1;
 	}
 	if ( iy >= STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT ) {
 		// normalize output
-	    hx = ( ( hx - 0x00100000 ) | ( ( iy + STDLIB_CONSTANT_FLOAT64_EXPONENT_BIAS ) << 20 ) );
+		hx = ( ( hx - 0x00100000 ) | ( ( iy + STDLIB_CONSTANT_FLOAT64_EXPONENT_BIAS ) << 20 ) );
 		stdlib_base_float64_from_words( (uint32_t)( hx | sx ), lx, &xc );
 	} else {
 		// subnormal output
-	    n = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT - iy;
-	    if ( n <= 20 ) {
+		n = STDLIB_CONSTANT_FLOAT64_MIN_BASE2_EXPONENT - iy;
+		if ( n <= 20 ) {
 			lx = ( lx >> n ) | ( (uint32_t)hx << ( 32 - n ) );
 			hx >>= n;
-	    } else if ( n <= 31 ) {
+		} else if ( n <= 31 ) {
 			lx = ( hx << ( 32 - n ) ) | ( lx >> n );
 			hx = sx;
-	    } else {
+		} else {
 			lx = hx >> ( n - 32 );
 			hx = sx;
-	    }
+		}
 		stdlib_base_float64_from_words( (uint32_t)( hx | sx ), lx, &xc );
 
 		// create necessary signal

lib/node_modules/@stdlib/math/base/special/fmod/test/fixtures/julia/large_small.json

@@ -38,9 +38,9 @@ julia> gen( x, y, \"data.json\" );
 ```
 """
 function gen( x, y, name )
-	z = Array{Float64}( undef, length(x) );
+	z = Array{Float64}( undef, length( x ) );
 	for i in eachindex(x)
-		z[ i ] = mod(x[i], y[i])
+		z[ i ] = rem( x[ i ], y[ i ] )
 	end
 
 	# Store data to be written to file as a collection:
@@ -85,3 +85,18 @@ gen( x, y, "small_large.json" );
 x = rand( 5001 ) .* 5e20;
 y = rand( 5001 ) .* 10;
 gen( x, y, "large_small.json" );
+
+# x positive, y negative:
+x = range( 1.0, stop = 709.78, length = 1000 );
+y = range( -709.78, stop = -1.0, length = 1000 );
+gen( x, y, "positive_negative.json" );
+
+# x negative, y positive:
+x = range( -709.78, stop = -1.0, length = 1000 );
+y = range( 1.0, stop = 709.78, length = 1000 );
+gen( x, y, "negative_positive.json" );
+
+# x negative, y negative:
+x = range( -709.78, stop = -1.0, length = 1000 );
+y = range( -709.78, stop = -1.0, length = 1000 );
+gen( x, y, "negative_negative.json" );

lib/node_modules/@stdlib/math/base/special/fmod/test/fixtures/julia/negative_negative.json

@@ -31,6 +31,9 @@ var subnormalResults = require( './fixtures/julia/subnormal_results.json' );
 var smallSmall = require( './fixtures/julia/small_small.json' );
 var smallLarge = require( './fixtures/julia/small_large.json' );
 var largeSmall = require( './fixtures/julia/large_small.json' );
+var negativePositive = require( './fixtures/julia/negative_positive.json' );
+var positiveNegative = require( './fixtures/julia/positive_negative.json' );
+var negativeNegative = require( './fixtures/julia/negative_negative.json' );
 
 
 // TESTS //
@@ -109,6 +112,57 @@ tape( 'the function evaluates the modulus function (small `x`, small `y`)', func
 	t.end();
 });
 
+tape( 'the function evaluates the modulus function (positive `x`, negative `y`)', function test( t ) {
+	var expected;
+	var actual;
+	var x;
+	var y;
+	var i;
+
+	x = positiveNegative.x;
+	y = positiveNegative.y;
+	expected = positiveNegative.expected;
+	for ( i = 0; i < x.length; i++ ) {
+		actual = fmod( x[ i ], y[ i ] );
+		t.equal( actual, expected[ i ], 'fmod('+x[ i ]+','+y[ i ]+') returns '+expected[ i ] );
+	}
+	t.end();
+});
+
+tape( 'the function evaluates the modulus function (negative `x`, positive `y`)', function test( t ) {
+	var expected;
+	var actual;
+	var x;
+	var y;
+	var i;
+
+	x = negativePositive.x;
+	y = negativePositive.y;
+	expected = negativePositive.expected;
+	for ( i = 0; i < x.length; i++ ) {
+		actual = fmod( x[ i ], y[ i ] );
+		t.equal( actual, expected[ i ], 'fmod('+x[ i ]+','+y[ i ]+') returns '+expected[ i ] );
+	}
+	t.end();
+});
+
+tape( 'the function evaluates the modulus function (negative `x`, negative `y`)', function test( t ) {
+	var expected;
+	var actual;
+	var x;
+	var y;
+	var i;
+
+	x = negativeNegative.x;
+	y = negativeNegative.y;
+	expected = negativeNegative.expected;
+	for ( i = 0; i < x.length; i++ ) {
+		actual = fmod( x[ i ], y[ i ] );
+		t.equal( actual, expected[ i ], 'fmod('+x[ i ]+','+y[ i ]+') returns '+expected[ i ] );
+	}
+	t.end();
+});
+
 tape( 'the function returns `NaN` if provided `NaN` for `y`', function test( t ) {
 	var v;