feat: serialize and deserialize model

Author: stropitek

Makefile

@@ -3,7 +3,7 @@ CXX = em++
 
 CFLAGS = -Wall -Wconversion -O3 -fPIC --memory-init-file 0
 BUILD_DIR=dist
-EXPORTED_FUNCTIONS="['_parse_command_line', '_create_svm_nodes', '_add_instance', '_libsvm_train_problem', '_libsvm_train', '_libsvm_predict_one', '_get_svr_epsilon', '_svm_free_model', '_svm_get_svm_type', '_svm_get_nr_sv', '_svm_get_nr_class', '_svm_get_sv_indices', '_svm_get_labels', '_libsvm_cross_validation', '_free_problem']"
+EXPORTED_FUNCTIONS="['_parse_command_line', '_create_svm_nodes', '_add_instance', '_libsvm_train_problem', '_libsvm_train', '_libsvm_predict_one', '_get_svr_epsilon', '_svm_free_model', '_svm_get_svm_type', '_svm_get_nr_sv', '_svm_get_nr_class', '_svm_get_sv_indices', '_svm_get_labels', '_libsvm_cross_validation', '_free_problem', '_serialize_model', '_deserialize_model']"
 
 all: wasm asm
 
@@ -14,7 +14,7 @@ wasm: js-interfaces.c svm.o libsvm/svm.h
 	mkdir -p $(BUILD_DIR)/wasm; $(CC) $(CFLAGS) js-interfaces.c svm.o -o $(BUILD_DIR)/wasm/libsvm.js --pre-js src/wasmPreJS.js -s -s BINARYEN_ASYNC_COMPILATION=1 -s NO_FILESYSTEM=1 -s BINARYEN=1 -s "BINARYEN_METHOD='native-wasm'" -s ALLOW_MEMORY_GROWTH=1 -s EXPORTED_FUNCTIONS=$(EXPORTED_FUNCTIONS)
 
 asm: js-interfaces.c svm.o libsvm/svm.h
-	mkdir -p $(BUILD_DIR)/asm; $(CC) $(CFLAGS) js-interfaces.c svm.o -o $(BUILD_DIR)/asm/libsvm.js --pre-js src/asmPreJS.js -s -s NO_FILESYSTEM=1 -s ALLOW_MEMORY_GROWTH=1 -s EXPORTED_FUNCTIONS=$(EXPORTED_FUNCTIONS)
+	mkdir -p $(BUILD_DIR)/asm; $(CC) $(CFLAGS) js-interfaces.c svm.o -o $(BUILD_DIR)/asm/libsvm.js --pre-js src/asmPreJS.js -s ALLOW_MEMORY_GROWTH=1 -s EXPORTED_FUNCTIONS=$(EXPORTED_FUNCTIONS)
 
 clean:
 	rm -f *~ js-interfaces.o ./svm.o

examples/xor.js

@@ -1,12 +1,17 @@
 'use strict';
 
 function xor(SVM) {
-    let svm = new SVM();
-    const features = [[1,1],[-1, -1],[1,-1],[-1, 1]];
-    const labels = [1,1,-1,-1];
+    let svm = new SVM({
+        kernel: SVM.KERNEL_TYPES.RBF,
+        type: SVM.SVM_TYPES.C_SVC,
+        gamma: 1,
+        cost: 1
+    });
+    const features = [[0,0],[1, 1],[1,0],[0, 1]];
+    const labels = [0, 0, 1, 1];
     svm.train(features, labels);
-    for(var i=0; i<features.length; i++) {
-        var pred = svm.predictOne(features[i]);
+    for(let i=0; i<features.length; i++) {
+        const pred = svm.predictOne(features[i]);
         console.log(`actual: ${labels[i]}, predicted: ${pred}`);
     }
 

js-interfaces.c

@@ -119,6 +119,30 @@ void add_instance(struct svm_problem* prob, double* features, int nb_dimensions,
     prob->y[i] = y;
 }
 
+char* serialize_model(struct svm_model* model)
+{
+    int success = svm_save_model("testfile.txt", model);
+    if(success < 0) return success;
+    FILE *f = fopen("testfile.txt", "rb");
+    fseek(f, 0, SEEK_END);
+    long fsize = ftell(f);
+    fseek(f, 0, SEEK_SET);  //same as rewind(f);
+
+    char *string = malloc(fsize + 1);
+    fread(string, fsize, 1, f);
+    fclose(f);
+
+    string[fsize] = 0;
+    return string;
+}
+
+struct svm_model* deserialize_model(const char* serialized) {
+    FILE *f = fopen("testfile.txt", "w");
+    fprintf(f, "%s", serialized);
+    fclose(f);
+    return svm_load_model("testfile.txt");
+}
+
 struct svm_problem* create_svm_nodes(int nb_features, int nb_dimensions)
 {
 	struct svm_problem* prob = Malloc(struct svm_problem, 1);

js-interfaces.h

@@ -11,6 +11,8 @@ void print_null(const char *s);
 void exit_with_help();
 void parse_command_line(const char* input_command, struct svm_parameter* param);
 void add_instance(struct svm_problem* prob, double* features, int nb_dimensions, double y, int i);
+char* serialize_model(struct svm_model* model);
+struct svm_model* deserialize_model(const char* serialized);
 struct svm_problem* create_svm_nodes(int nb_features, int nb_dimensions);
 void svm_free_model(struct svm_model *model);
 struct svm_model* libsvm_train_problem(struct svm_problem* prob, const char* command);

src/loadSVM.js

@@ -14,6 +14,9 @@ module.exports = function (libsvm) {
     const svm_free_model = libsvm.cwrap('svm_free_model', null, ['number']);
     const svm_cross_validation = libsvm.cwrap('libsvm_cross_validation', null, ['number', 'string', 'number', 'number']);
     const free_problem = libsvm.cwrap('free_problem', null, ['number']);
+    const serialize_model = libsvm.cwrap('serialize_model', 'number', ['number']);
+    const deserialize_model = libsvm.cwrap('deserialize_model', 'number', ['string']);
+
     /* eslint-enable camelcase */
 
     const SVM_TYPES = {
@@ -110,8 +113,22 @@ module.exports = function (libsvm) {
             return getIntArrayFromModel(svm_get_sv_indices, this.model, nSV)
                 .map(i => i - 1);
         }
+
+        serializeModel() {
+            if(!this.model) throw new Error('Cannot serialize model. No model was trained');
+            const result = serialize_model(this.model);
+            const str = libsvm.Pointer_stringify(result);
+            libsvm._free(result);
+            return str;
+        }
     }
 
+    SVM.load = function(serializedModel) {
+        const svm = new SVM();
+        svm.model = deserialize_model(serializedModel);
+        return svm;
+    };
+
     SVM.SVM_TYPES = SVM_TYPES;
     SVM.KERNEL_TYPES = KERNEL_TYPES;