Add Cephes benchmark snippet

Author: kgryte

tools/snippets/benchmark/c/cephes/Makefile

@@ -0,0 +1,95 @@
+
+# VARIABLES #
+
+ifndef VERBOSE
+	QUIET := @
+endif
+
+# Specify the path to Cephes:
+CEPHES ?=
+
+# Determine the OS:
+#
+# [1]: https://en.wikipedia.org/wiki/Uname#Examples
+# [2]: http://stackoverflow.com/a/27776822/2225624
+OS ?= $(shell uname)
+ifneq (, $(findstring MINGW,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring MSYS,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring CYGWIN,$(OS)))
+	OS := WINNT
+endif
+endif
+endif
+
+# Define the program used for compiling C source files:
+ifdef C_COMPILER
+	CC := $(C_COMPILER)
+else
+	CC := gcc
+endif
+
+# Define the command-line options when compiling C files:
+CFLAGS ?= \
+	-std=c99 \
+	-O3 \
+	-Wall \
+	-pedantic
+
+# Determine whether to generate [position independent code][1]:
+#
+# [1]: https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#Code-Gen-Options
+# [2]: http://stackoverflow.com/questions/5311515/gcc-fpic-option
+ifeq ($(OS), WINNT)
+	fPIC ?=
+else
+	fPIC ?= -fPIC
+endif
+
+# List of Cephes source files (e.g., `double/sindg.c double/polyn.c double/mtherr.c`:
+src_cephes :=
+
+# List of C targets:
+c_targets := benchmark.out
+
+
+# TARGETS #
+
+# Default target.
+#
+# This target is the default target.
+
+all: $(c_targets)
+
+.PHONY: all
+
+
+# Compile C source.
+#
+# This target compiles C source files.
+
+$(c_targets): %.out: %.c
+	$(QUIET) $(CC) $(CFLAGS) $(fPIC) -o $@ $(addprefix $(CEPHES)/,$(src_cephes)) $< -lm
+
+
+# Run a benchmark.
+#
+# This target runs a benchmark.
+
+run: $(c_targets)
+	$(QUIET) ./$<
+
+.PHONY: run
+
+
+# Perform clean-up.
+#
+# This target removes generated files.
+
+clean:
+	$(QUIET) -rm -f *.o *.out
+
+.PHONY: clean

tools/snippets/benchmark/c/cephes/benchmark.c

@@ -0,0 +1,116 @@
+/**
+* Benchmark Cephes `TODO`.
+*/
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <sys/time.h>
+
+#define NAME "TODO"
+#define ITERATIONS 1000000
+#define REPEATS 3
+
+/**
+* Prints the TAP version.
+*/
+void print_version() {
+	printf( "TAP version 13\n" );
+}
+
+/**
+* Prints the TAP summary.
+*
+* @param total     total number of tests
+* @param passing   total number of passing tests
+*/
+void print_summary( int total, int passing ) {
+	printf( "#\n" );
+	printf( "1..%d\n", total ); // TAP plan
+	printf( "# total %d\n", total );
+	printf( "# pass  %d\n", passing );
+	printf( "#\n" );
+	printf( "# ok\n" );
+}
+
+/**
+* Prints benchmarks results.
+*
+* @param elapsed   elapsed time in seconds
+*/
+void print_results( double elapsed ) {
+	double rate = (double)ITERATIONS / elapsed;
+	printf( "  ---\n" );
+	printf( "  iterations: %d\n", ITERATIONS );
+	printf( "  elapsed: %0.9f\n", elapsed );
+	printf( "  rate: %0.9f\n", rate );
+	printf( "  ...\n" );
+}
+
+/**
+* Returns a clock time.
+*
+* @return clock time
+*/
+double tic() {
+	struct timeval now;
+	gettimeofday( &now, NULL );
+	return (double)now.tv_sec + (double)now.tv_usec/1.0e6;
+}
+
+/**
+* Generates a random double on the interval [0,1].
+*
+* @return random double
+*/
+double rand_double() {
+	int r = rand();
+	return (double)r / ( (double)RAND_MAX + 1.0 );
+}
+
+/**
+* Runs a benchmark.
+*
+* @return elapsed time in seconds
+*/
+double benchmark() {
+	double elapsed;
+	double x;
+	double y;
+	double t;
+	int i;
+
+	t = tic();
+	for ( i = 0; i < ITERATIONS; i++ ) {
+		x = 0.0; // TODO
+		y = 0.0; // TODO
+		if ( y != y ) {
+			printf( "should not return NaN\n" );
+			break;
+		}
+	}
+	elapsed = tic() - t;
+	if ( y != y ) {
+		printf( "should not return NaN\n" );
+	}
+	return elapsed;
+}
+
+/**
+* Main execution sequence.
+*/
+int main( void ) {
+	double elapsed;
+	int i;
+
+	// Use the current time to seed the random number generator:
+	srand( time( NULL ) );
+
+	print_version();
+	for ( i = 0; i < REPEATS; i++ ) {
+		printf( "# c::cephes::%s\n", NAME );
+		elapsed = benchmark();
+		print_results( elapsed );
+		printf( "ok %d benchmark finished\n", i+1 );
+	}
+	print_summary( REPEATS, REPEATS );
+}