Fix cgo pointer issues

.travis.yml

@@ -1,16 +1,16 @@
 language: go
+dist: bionic
 go:
- - "1.9"
- - "1.10"
- - "1.11"
- - "1.12"
+ - "1.13"
+ - "1.14"
+arch:
+ - amd64
+ - arm64
 env:
- # Temporary workaround for go 1.6
- - GODEBUG=cgocheck=0
 before_install:
  - sudo apt-get update -qq
  - sudo apt-get install -qq libatlas-base-dev
- - cd /tmp && wget http://www.csie.ntu.edu.tw/~cjlin/liblinear/oldfiles/liblinear-1.94.tar.gz && tar xf liblinear-1.94.tar.gz && cd liblinear-1.94 && make lib && sudo install -vm644 linear.h /usr/include && sudo install -vm755 liblinear.so.1 /usr/lib && sudo ln -sfv liblinear.so.1 /usr/lib/liblinear.so
+ - cd /tmp && wget https://www.csie.ntu.edu.tw/~cjlin/liblinear/oldfiles/liblinear-1.94.tar.gz && tar xf liblinear-1.94.tar.gz && cd liblinear-1.94 && make lib && sudo install -vm644 linear.h /usr/include && sudo install -vm755 liblinear.so.1 /usr/lib && sudo ln -sfv liblinear.so.1 /usr/lib/liblinear.so
  - cd $TRAVIS_BUILD_DIR
 install:
  - go get github.com/smartystreets/goconvey/convey

ensemble/multisvc_test.go

@@ -1,11 +1,12 @@
 package ensemble
 
 import (
+	"io/ioutil"
+	"testing"
+
 	"github.com/sjwhitworth/golearn/base"
 	"github.com/sjwhitworth/golearn/evaluation"
 	. "github.com/smartystreets/goconvey/convey"
-	"io/ioutil"
-	"testing"
 )
 
 func TestMultiSVMUnweighted(t *testing.T) {
@@ -14,40 +15,43 @@ func TestMultiSVMUnweighted(t *testing.T) {
 		So(err, ShouldBeNil)
 		X, Y := base.InstancesTrainTestSplit(inst, 0.4)
 
-		m := NewMultiLinearSVC("l1", "l2", true, 1.0, 1e-4, nil)
-		m.Fit(X)
-
-		Convey("Predictions should work...", func() {
-			predictions, err := m.Predict(Y)
-			So(err, ShouldEqual, nil)
-			cf, err := evaluation.GetConfusionMatrix(Y, predictions)
-			So(err, ShouldEqual, nil)
-			So(evaluation.GetAccuracy(cf), ShouldBeGreaterThan, 0.70)
-		})
-
-		Convey("Saving should work...", func() {
-			f, err := ioutil.TempFile("", "tree")
-			So(err, ShouldBeNil)
-			err = m.Save(f.Name())
+		Convey("Fitting should work...", func() {
+			m := NewMultiLinearSVC("l1", "l2", true, 1.0, 1e-4, nil)
+			err := m.Fit(X)
 			So(err, ShouldBeNil)
 
-			Convey("Loading should work...", func() {
-				mLoaded := NewMultiLinearSVC("l1", "l2", true, 1.00, 1e-8, nil)
-				err := mLoaded.Load(f.Name())
+			Convey("Predictions should work...", func() {
+				predictions, err := m.Predict(Y)
+				So(err, ShouldEqual, nil)
+				cf, err := evaluation.GetConfusionMatrix(Y, predictions)
+				So(err, ShouldEqual, nil)
+				So(evaluation.GetAccuracy(cf), ShouldBeGreaterThan, 0.70)
+			})
+
+			Convey("Saving should work...", func() {
+				f, err := ioutil.TempFile("", "tree")
+				So(err, ShouldBeNil)
+				err = m.Save(f.Name())
 				So(err, ShouldBeNil)
 
-				Convey("Predictions should be the same...", func() {
-					originalPredictions, err := m.Predict(Y)
-					So(err, ShouldBeNil)
-					newPredictions, err := mLoaded.Predict(Y)
+				Convey("Loading should work...", func() {
+					mLoaded := NewMultiLinearSVC("l1", "l2", true, 1.00, 1e-8, nil)
+					err := mLoaded.Load(f.Name())
 					So(err, ShouldBeNil)
-					So(base.InstancesAreEqual(originalPredictions, newPredictions), ShouldBeTrue)
+
+					Convey("Predictions should be the same...", func() {
+						originalPredictions, err := m.Predict(Y)
+						So(err, ShouldBeNil)
+						newPredictions, err := mLoaded.Predict(Y)
+						So(err, ShouldBeNil)
+						So(base.InstancesAreEqual(originalPredictions, newPredictions), ShouldBeTrue)
+					})
+
 				})
 
 			})
 
 		})
-
 	})
 }
 

linear_models/integration.cpp

@@ -0,0 +1,93 @@
+/*
+ * This file contains functions related to creating + freeing
+ * objects on behalf of the go runtime
+ */
+
+#include "linear.h"
+#include <stdlib.h>
+
+extern "C" {
+
+/* NOTE: the Golang versions of the structures must call the corresponding
+ * Free functions via runtime.SetFinalize */
+/* CreateCProblem allocates a new struct problem outside of Golang's
+ * garbage collection. */
+struct problem *CreateCProblem() {
+    auto ret = new problem();
+    *ret = {}; // < Clear all fields
+    return ret;
+}
+
+/* CreateCModel allocates a new struct model outside of Golang's 
+ * garbage collection. */
+struct model *CreateCModel() {
+    auto ret = new model();
+    *ret = {}; // < Clear all fields
+    return ret;
+}
+
+/* CreateCParameter allocates a new struct parameter outside of
+ * Golang's garbage collection.*/
+struct parameter *CreateCParameter() {
+    return reinterpret_cast<struct parameter*>(calloc(1, sizeof(struct parameter)));
+}
+
+/* Free's a previously allocated problem and all its data */
+void FreeCProblem(struct problem *p) {
+    if (p->y != nullptr) {
+        free(p->y);
+        p->y = nullptr;
+    }
+    if (p->x != nullptr) {
+        free(p->x);
+        p->x = nullptr;
+    }
+    delete p;
+}
+
+/* free's a model with libsvm's internal routines */
+void FreeCModel(struct model *m) {
+    free_model_content(m);
+    delete m;
+}
+
+/* free's a parameter via libsvm */
+void FreeCParameter(struct parameter *p) {
+    if (p == nullptr) {
+        return;
+    }
+    free(p);
+}
+
+/* Allocates a vector of doubles for storing target values
+ * outside of Go's garbage collection */
+int AllocateLabelsForProblem (struct problem *p, int numValues) {
+    p->y = reinterpret_cast<double *>(malloc(sizeof(double) * numValues));
+    return p->y == nullptr;
+}
+
+/* Utility method used to set the target value for a particular
+ * input row */
+void AssignLabelForProblem(struct problem *p, int i, double d) {
+    p->y[i] = d;
+}
+
+/* Allocates a buffer of input rows and inserts the per-row values */
+int RiffleFeatures(struct problem *p, int num_offsets, int* row_offsets, struct feature_node *features) {
+
+    // Allocate space for the feature node buffer.
+    p->x = reinterpret_cast<struct feature_node**>(
+        calloc(num_offsets, sizeof(struct feature_node *))
+    );
+    if (p->x == nullptr) {
+        return -1;
+    }
+
+    for (int i = 0; i < num_offsets; i++) {
+        int offset = row_offsets[i];
+        p->x[i] = features + offset;
+    }
+    return 0;
+}
+
+} /* extern "C" */

linear_models/integration.h

@@ -0,0 +1,19 @@
+#ifndef _H_INTEGRATION_
+#define _H_INTEGRATION_
+
+#include "linear.h"
+
+struct problem *CreateCProblem();
+void FreeCProblem(struct problem*);
+struct model *CreateCModel();
+void FreeCModel(struct model*);
+struct parameter *CreateCParameter();
+void FreeCParameter(struct parameter*);
+// Allocates memory outside of golang for describing feature
+// vectors.
+int RiffleFeatures(struct problem *p, int num_offsets, int* row_offsets, struct feature_node *features);
+int AllocateLabelsForProblem(struct problem *, int);
+void AssignLabelForProblem(struct problem *, int, double);
+struct feature_node *GetFeatureNodeForIndex(struct problem *, int, int);
+
+#endif