From e3a81044ab546bead22367428a20b131f39e0195 Mon Sep 17 00:00:00 2001
From: Julian Weigt <juw@posteo.de>
Date: Fri, 9 Jan 2026 16:56:30 +0000
Subject: Invoke malloc more often because we run out of memory?

---
 charf.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/charf.c b/charf.c
index 2552b06..101722b 100644
--- a/charf.c
+++ b/charf.c
@@ -36,7 +36,7 @@ static const int K=24;
 
 /*given function df[0] on domain [0,M-1], compute derivatives f' until f^{(K)} and store f^{(K)} in df*/
 void differentiate(VALUETYPE* f, VALUETYPE* df, int D, int k){
-	VALUETYPE df0[D];
+	VALUETYPE* df0 = malloc(D*sizeof(VALUETYPE));
 	/*Set zeroth derivative to be f.*/
 	for(int i=0; i<D; i++){
 		df0[i] = f[i];
@@ -53,6 +53,7 @@ void differentiate(VALUETYPE* f, VALUETYPE* df, int D, int k){
 	for(int i=0;i<D;i++) printf("%+6.1f ",to_double(df[i]));
 	printf("\n");
 	*/
+	free(df0);
 }
 
 /*given function f on domain [0,D-1] compute pth root of integral of |f|^p*/
@@ -71,8 +72,8 @@ void compute_maximalfunction(VALUETYPE* f, VALUETYPE* Mf, int D){
 	/*Af[i][j] will be the average of f on [min(i,j),max(i,j)]*/
 	//VALUETYPE Af[N][N];
 	/*Apparently may become too big for stack or something so have to use malloc instead.*/
-	VALUETYPE* Sf[N];
-	VALUETYPE* Af[N];
+	VALUETYPE** Sf = malloc(D*sizeof(VALUETYPE*));
+	VALUETYPE** Af = malloc(D*sizeof(VALUETYPE*));
 	for(int i=0; i<D; i++){
 		Sf[i] = malloc(D*sizeof(VALUETYPE));
 		Af[i] = malloc(D*sizeof(VALUETYPE));
@@ -115,6 +116,8 @@ void compute_maximalfunction(VALUETYPE* f, VALUETYPE* Mf, int D){
 		free(Af[i]);
 		free(Sf[i]);
 	}
+	free(Af);
+	free(Sf);
 }
 
 bool over_threshold_charf(double t, int k){
@@ -122,15 +125,17 @@ bool over_threshold_charf(double t, int k){
 }
 
 void compute(EXPTYPE p, int D, VALUETYPE* f, VALUETYPE* records){
-	VALUETYPE Mf[N];
+	VALUETYPE* Mf = malloc(D*sizeof(VALUETYPE));
 	/*This is the only O(D^2) operation in here so makes a lot of sense to only compute once and avoid repeating it.*/
 	compute_maximalfunction(f,Mf,D);
 
 	/*Allocate memory for derivatives.*/
-	VALUETYPE df[2][N];
-	VALUETYPE dMf[2][N];
+	VALUETYPE* df[2];
+	VALUETYPE* dMf[2];
 
 	for(int i=0; i<=1; i++){
+		df[i] = malloc(D*sizeof(VALUETYPE));
+		dMf[i] = malloc(D*sizeof(VALUETYPE));
 		for(int n=0; n<D; n++){
 			df[i][n] = f[n];
 			dMf[i][n] = Mf[n];
@@ -184,6 +189,13 @@ void compute(EXPTYPE p, int D, VALUETYPE* f, VALUETYPE* records){
 			records[k] = maximum(records[k],r);
 		}
 	}
+
+
+	for(int i=0; i<=1; i++){
+		free(df[i]);
+		free(dMf[i]);
+	}
+	free(Mf);
 }
 
 /*Generates all characteristic functions of length up N.*/
@@ -235,7 +247,7 @@ void* compute_chunk(void* arguments){
 	/*exponent p of the L^p norm to consider*/
 	EXPTYPE p = int_to_exptype(1);
 
-	VALUETYPE f[N];
+	VALUETYPE* f = malloc(N*sizeof(VALUETYPE));
 	int d = generate_function(f,i);
 	while(d >= 0){
 		if(d > *domain_current){
@@ -245,7 +257,8 @@ void* compute_chunk(void* arguments){
 		compute(p,d,f,records);
 		i += NUM_THREADS;
 		d = generate_function(f,i);
-	}	
+	}
+	free(f);
 }
 
 int main() {
-- 
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