Question

我很困惑为什么删除[]（以及删除以及此类问题）失败，当我尝试在指向新指针的指针上调用它时

// Start with output first
float* sigmas = new float[_M];
float* sigmasNext = new float[_M];
for (int i = 0; i < _M; i++) // Loop through and attempt to learn the outputs
{
    sigmas[i] = _output[i].Learn(inputValues, outputValues[i]); // Learn
}

// Then the hidden layers
float* weights;

// The first layer
for (int j = 0; j < _H[0]; j++)
{
    weights = new float[_M];
    for (int k = 0; k < _M; k++)
    {
        weights[k] = _output[k].GetWeights()[j];
    }
    sigmasNext[j] = _hidden[0][j].Learn(inputValues, sigmas, weights, _M);
    delete [] weights;
}
delete [] sigmas;

// The other hidden layers
for (int i = 1; i < _Hcount; i++)
{
    sigmas = sigmasNext;
    sigmasNext = new float[_H[i - 1]];
    for (int j = 0; j < _H[i]; j++)
    {
        weights = new float[_H[i - 1]];
        for (int k = 0; k < _H[i - 1]; k++)
        {
            weights[k] = _hidden[i - 1][k].GetWeights()[j];
        }
        sigmasNext[j] = _hidden[i][j].Learn(inputValues, sigmas, weights, _H[i - 1]);
        delete [] weights;
    }
    delete [] sigmas;
}

了解（）：

float sigma;

// Get the output of this neuron
float net = Net(inputs);
float out = FireOnNet(net);
float derive = DerivedValue(net);

// Learning
// Sigma(hidden)[i] = sum(sigma[k] * w[k]; 1 -> K) * f'(net)
// deltaW[i] = alpha * sigma * net
if (_type == Output)
{
    throw 0; // Should probably throw a real exception here
}
else // if (_type == Hidden)
{
    sigma = 0;
    for (int i = 0; i < sigmaCount; i++)
    {
        sigma += sigmas[i] * weights[i] * derive;
    }
    sigma *= derive;
}
_deltaWeights[0] += alpha * sigma * 1; // Adjust the BIAS weight //////
for (int i = 1; i < _numOfWeights; i++) // Adjust the other weights
{
    _deltaWeights[i] += alpha * sigma * inputs[i - 1];
}

return sigma;

我崩溃了第二个删除[] sigmas; （在第一个代码块的末尾）但是如果sigmas指向由sigmasNext分配的堆，为什么它会崩溃？在保留下一个循环的同时解除分配sigmasNext的正确方法是什么？

Answer 1

您正在分配一个_M浮动数组

float* sigmasNext = new float[_M];

并写入元素0 .._ H [0]

for (int j = 0; j < _H[0]; j++)
    sigmasNext[j] = ...

分别写出元素0 .._ H [i]

for (int j = 0; j < _H[i]; j++)
    sigmasNext[j] = ...

我猜你正在向数组中写入多于_M个元素，从而破坏了内存管理结构，从而导致delete []崩溃。

如果你没有使用原始指针而是使用像vector这样的STL容器，那就不会发生这种情况。 vector将在调试模式下断言，并告诉您是否访问无效索引处的元素。

在指向new [] d array

1 个答案: