diff options
Diffstat (limited to 'libm/double/fltest.c')
| -rw-r--r-- | libm/double/fltest.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/libm/double/fltest.c b/libm/double/fltest.c new file mode 100644 index 000000000..f2e3d8665 --- /dev/null +++ b/libm/double/fltest.c @@ -0,0 +1,272 @@ +/* fltest.c + * Test program for floor(), frexp(), ldexp() + */ + +/* +Cephes Math Library Release 2.1: December, 1988 +Copyright 1984, 1987, 1988 by Stephen L. Moshier +Direct inquiries to 30 Frost Street, Cambridge, MA 02140 +*/ + + + +#include <math.h> +extern double MACHEP; +#define UTH -1023 + +main() +{ +double x, y, y0, z, f, x00, y00; +int i, j, k, e, e0; +int errfr, errld, errfl, underexp, err, errth, e00; +double frexp(), ldexp(), floor(); + + +/* +if( 1 ) + goto flrtst; +*/ + +printf( "Testing frexp() and ldexp().\n" ); +errfr = 0; +errld = 0; +underexp = 0; +f = 1.0; +x00 = 2.0; +y00 = 0.5; +e00 = 2; + +for( j=0; j<20; j++ ) +{ +if( j == 10 ) + { + f = 1.0; + x00 = 2.0; + e00 = 1; +/* Find 2**(2**10) / 2 */ +#ifdef DEC + for( i=0; i<5; i++ ) +#else + for( i=0; i<9; i++ ) +#endif + { + x00 *= x00; + e00 += e00; + } + y00 = x00/2.0; + x00 = x00 * y00; + e00 += e00; + y00 = 0.5; + } +x = x00 * f; +y0 = y00 * f; +e0 = e00; +for( i=0; i<2200; i++ ) + { + x /= 2.0; + e0 -= 1; + if( x == 0.0 ) + { + if( f == 1.0 ) + underexp = e0; + y0 = 0.0; + e0 = 0; + } + y = frexp( x, &e ); + if( (e0 < -1023) && (e != e0) ) + { + if( e == (e0 - 1) ) + { + e += 1; + y /= 2.0; + } + if( e == (e0 + 1) ) + { + e -= 1; + y *= 2.0; + } + } + err = y - y0; + if( y0 != 0.0 ) + err /= y0; + if( err < 0.0 ) + err = -err; + if( e0 > -1023 ) + errth = 0.0; + else + {/* Denormal numbers may have rounding errors */ + if( e0 == -1023 ) + { + errth = 2.0 * MACHEP; + } + else + { + errth *= 2.0; + } + } + + if( (x != 0.0) && ((err > errth) || (e != e0)) ) + { + printf( "Test %d: ", j+1 ); + printf( " frexp( %.15e) =?= %.15e * 2**%d;", x, y, e ); + printf( " should be %.15e * 2**%d\n", y0, e0 ); + errfr += 1; + } + y = ldexp( x, 1-e0 ); + err = y - 1.0; + if( err < 0.0 ) + err = -err; + if( (err > errth) && ((x == 0.0) && (y != 0.0)) ) + { + printf( "Test %d: ", j+1 ); + printf( "ldexp( %.15e, %d ) =?= %.15e;", x, 1-e0, y ); + if( x != 0.0 ) + printf( " should be %.15e\n", f ); + else + printf( " should be %.15e\n", 0.0 ); + errld += 1; + } + if( x == 0.0 ) + { + break; + } + } +f = f * 1.08005973889; +} + + +x = 2.22507385850720138309e-308; +for (i = 0; i < 52; i++) + { + y = ldexp (x, -i); + z = ldexp (y, i); + if (x != z) + { + printf ("x %.16e, i %d, y %.16e, z %.16e\n", x, i, y, z); + errld += 1; + } + } + + +if( (errld == 0) && (errfr == 0) ) + { + printf( "No errors found.\n" ); + } + +flrtst: + +printf( "Testing floor().\n" ); +errfl = 0; + +f = 1.0/MACHEP; +x00 = 1.0; +for( j=0; j<57; j++ ) +{ +x = x00 - 1.0; +for( i=0; i<128; i++ ) + { + y = floor(x); + if( y != x ) + { + flierr( x, y, j ); + errfl += 1; + } +/* Warning! the if() statement is compiler dependent, + * since x-0.49 may be held in extra precision accumulator + * so would never compare equal to x! The subroutine call + * y = floor() forces z to be stored as a double and reloaded + * for the if() statement. + */ + z = x - 0.49; + y = floor(z); + if( z == x ) + break; + if( y != (x - 1.0) ) + { + flierr( z, y, j ); + errfl += 1; + } + + z = x + 0.49; + y = floor(z); + if( z != x ) + { + if( y != x ) + { + flierr( z, y, j ); + errfl += 1; + } + } + x = -x; + y = floor(x); + if( z != x ) + { + if( y != x ) + { + flierr( x, y, j ); + errfl += 1; + } + } + z = x + 0.49; + y = floor(z); + if( z != x ) + { + if( y != x ) + { + flierr( z, y, j ); + errfl += 1; + } + } + z = x - 0.49; + y = floor(z); + if( z != x ) + { + if( y != (x - 1.0) ) + { + flierr( z, y, j ); + errfl += 1; + } + } + x = -x; + x += 1.0; + } +x00 = x00 + x00; +} +y = floor(0.0); +if( y != 0.0 ) + { + flierr( 0.0, y, 57 ); + errfl += 1; + } +y = floor(-0.0); +if( y != 0.0 ) + { + flierr( -0.0, y, 58 ); + errfl += 1; + } +y = floor(-1.0); +if( y != -1.0 ) + { + flierr( -1.0, y, 59 ); + errfl += 1; + } +y = floor(-0.1); +if( y != -1.0 ) + { + flierr( -0.1, y, 60 ); + errfl += 1; + } + +if( errfl == 0 ) + printf( "No errors found in floor().\n" ); + +} + + +flierr( x, y, k ) +double x, y; +int k; +{ +printf( "Test %d: ", k+1 ); +printf( "floor(%.15e) =?= %.15e\n", x, y ); +} |