CODEWITHSUNDEEP
c++c++11operator-overloading
Karan Chahal
Karan Chahal

Reputation: 3

Using multiple operators with operator overloading gives strange error

I have a single class called FloatTensor. I have overloaded operators for + and * in that. Here is the code.


class FloatTensor {
    public:
    float val; // value of tensor 
    float grad; // value of grad
    Operation *frontOp =NULL, *backOp =NULL;
    FloatTensor* two;
    FloatTensor() {
        // default
    }

    FloatTensor(float val) {
        this->val = val;
    }

    FloatTensor(float val, Operation* op) {
        this->val = val;
        this->backOp = op;
    }

    void backward(float grad) {
        this->grad = grad;
        if(this->backOp != NULL) {
            this->backOp->backward(grad);
        }
    }
    FloatTensor exp() {
        this->frontOp = new ExponentOperation(this);
        return this->frontOp->compute();
    }

    FloatTensor operator * (FloatTensor &two) { 

        this->frontOp = new MultiplyOperation(this, &two);
        return this->frontOp->compute();
    }

    FloatTensor operator + (FloatTensor &two) { 
        this->frontOp = new AddOperation(this, &two);
        return this->frontOp->compute();
    }

    FloatTensor operator / (FloatTensor &two) { 

        this->frontOp = new DivideOperation(this, &two);
        return this->frontOp->compute();
    }

};

IN my main function when I try simple overloading, things work great

int main() {

    // X 
    FloatTensor x1(200); // heap declaration
    FloatTensor x2(300);

    // Weights
    FloatTensor w1(222);
    FloatTensor w2(907);

    FloatTensor temp = (x1*w1);

}

However when I try to overload this formula with more operators like this 

int main() {

    // X 
    FloatTensor x1(200); // heap declaration
    FloatTensor x2(300);

    // Weights
    FloatTensor w1(222);
    FloatTensor w2(907);

    FloatTensor temp = (x1*w1) + (x2*w2);

}

I get this error:

no operator "+" matches these operands -- operand types are: FloatTensor + FloatTensor

I would be very grateful if someone can explain why this is happening. I observed that this works:

x1*w1*x2*x1;
x1*w1 + x2;

But x1*w1 + x2*w2 does not.

Very strange..

Upvotes: 0

Views: 41

Answers (1)

Vittorio Romeo
Vittorio Romeo

Reputation: 93264

Your operators accept a non-const lvalue reference as an argument. Temporaries do not bind to non-const lvalue references. To accept temporaries, use:

FloatTensor operator + (const FloatTensor &two)

Upvotes: 3

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