savepoint

examples/03_gcc_nested_function/example.c

@@ -0,0 +1,37 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "../../squiggle.h"
+
+int main(){
+    // set randomness seed
+		uint32_t* seed = malloc(sizeof(uint32_t));
+		*seed = 1000; // xorshift can't start with 0
+
+    float p_a = 0.8;
+    float p_b = 0.5;
+    float p_c = p_a * p_b;
+
+    int n_dists = 4;
+		
+		float sample_0(uint32_t* seed){ return 0; }
+		float sample_1(uint32_t* seed) { return 1; }
+		float sample_few(uint32_t* seed){ return random_to(1, 3, seed); }
+		float sample_many(uint32_t* seed){ return random_to(2, 10, seed); } 
+		
+    float (*samplers[])(uint32_t*) = { sample_0, sample_1, sample_few, sample_many };
+		float weights[] = { 1 - p_c, p_c / 2, p_c / 4, p_c / 4 };
+
+		int n_samples = 1000000;
+		float* result_many = (float *) malloc(n_samples * sizeof(float));
+		for(int i=0; i<n_samples; i++){
+      result_many[i] = mixture(samplers, weights, n_dists, seed);
+		}
+		
+		printf("result_many: [");
+		for(int i=0; i<100; i++){
+		  printf("%.2f, ", result_many[i]);
+		}
+		printf("]\n");
+}
+

examples/03_gcc_nested_function/makefile

@@ -0,0 +1,57 @@
+# Interface: 
+#   make
+#   make build
+#   make format
+#   make run
+
+# Compiler
+CC=gcc # required for nested functions
+# CC=tcc # <= faster compilation
+
+# Main file
+SRC=example.c
+OUTPUT=example
+
+## Dependencies
+MATH=-lm
+DEPENDENCIES=$(MATH)
+# OPENMP=-fopenmp
+
+## Flags
+DEBUG= #'-g'
+STANDARD=-std=gnu99 ## allows for nested functions.
+EXTENSIONS= #-fnested-functions
+WARNINGS=-Wall
+OPTIMIZED=-O3#-Ofast
+CFLAGS=$(DEBUG) $(STANDARD) $(EXTENSIONS) $(WARNINGS) $(OPTIMIZED)
+
+## Formatter
+STYLE_BLUEPRINT=webkit
+FORMATTER=clang-format -i -style=$(STYLE_BLUEPRINT)
+
+## make build
+build: $(SRC)
+	# gcc -std=gnu99 example.c -lm -o example
+	$(CC) $(CFLAGS) $(SRC) $(DEPENDENCIES) -o $(OUTPUT)
+
+format: $(SRC)
+	$(FORMATTER) $(SRC)
+
+run: $(SRC) $(OUTPUT)
+	./$(OUTPUT) && echo
+
+time-linux: 
+	@echo "Requires /bin/time, found on GNU/Linux systems" && echo
+	
+	@echo "Running 100x and taking avg time $(OUTPUT)"
+	@t=$$(/usr/bin/time -f "%e" -p bash -c 'for i in {1..100}; do $(OUTPUT); done' 2>&1 >/dev/null | grep real | awk '{print $$2}' ); echo "scale=2; 1000 * $$t / 100" | bc | sed "s|^|Time using 1 thread: |" | sed 's|$$|ms|' && echo
+
+## Profiling
+
+profile-linux: 
+	echo "Requires perf, which depends on the kernel version, and might be in linux-tools package or similar"
+	echo "Must be run as sudo"
+	$(CC) $(SRC) $(MATH) -o $(OUTPUT)
+	sudo perf record $(OUTPUT)
+	sudo perf report
+	rm perf.data

squiggle.h

@@ -95,14 +95,17 @@ float mixture(float (*samplers[])(uint32_t*), float* weights, int n_dists, uint3
         cumsummed_normalized_weights[i] = cumsummed_normalized_weights[i - 1] + weights[i]/sum_weights;
     }
 
-		float p = random_uniform(0, 1, seed);
 		float result;
+		int result_set_flag = 0;
+		float p = random_uniform(0, 1, seed);
 		for (int k = 0; k < n_dists; k++) {
 				if (p < cumsummed_normalized_weights[k]) {
 						result = samplers[k](seed);
+						result_set_flag = 1;
 						break;
 				}
 		}
+		if(result_set_flag == 0) result = samplers[n_dists-1](seed);
 
 		free(cumsummed_normalized_weights);
 		return result;

to-do.md

@@ -1,9 +1,10 @@
 
-- [ ] Add example for only one sample
-- [ ] Add example for many samples
+- [x] Add example for only one sample
+- [x] Add example for many samples
 - [ ] Use gcc extension to define functions nested inside main.
 - [ ] Use OpenMP for acceleration
 - [ ] Chain various mixture functions
 - [ ] Have some more complicated & realistic example
 - [ ] Add summarization functions, like mean, std, 90% ci (or all c.i.?)
 - [ ] Add beta distribution
+- [ ] Add a custom preprocessor to allow simple nested functions that don't rely on local scope?