Python numpy.clip函数代码示例

def lowess(x, y, f=2. / 3., iter=3):
    """lowess(x, y, f=2./3., iter=3) -> yest

    Lowess smoother: Robust locally weighted regression.
    The lowess function fits a nonparametric regression curve to a scatterplot.
    The arrays x and y contain an equal number of elements; each pair
    (x[i], y[i]) defines a data point in the scatterplot. The function returns
    the estimated (smooth) values of y.

    The smoothing span is given by f. A larger value for f will result in a
    smoother curve. The number of robustifying iterations is given by iter. The
    function will run faster with a smaller number of iterations.

    x and y should be numpy float arrays of equal length.  The return value is
    also a numpy float array of that length.

    e.g.
    >>> import numpy
    >>> x = numpy.array([4,  4,  7,  7,  8,  9, 10, 10, 10, 11, 11, 12, 12, 12,
    ...                 12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 16, 16,
    ...                 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 20, 20, 20, 20,
    ...                 20, 22, 23, 24, 24, 24, 24, 25], numpy.float)
    >>> y = numpy.array([2, 10,  4, 22, 16, 10, 18, 26, 34, 17, 28, 14, 20, 24,
    ...                 28, 26, 34, 34, 46, 26, 36, 60, 80, 20, 26, 54, 32, 40,
    ...                 32, 40, 50, 42, 56, 76, 84, 36, 46, 68, 32, 48, 52, 56,
    ...                 64, 66, 54, 70, 92, 93, 120, 85], numpy.float)
    >>> result = lowess(x, y)
    >>> len(result)
    50
    >>> print "[%0.2f, ..., %0.2f]" % (result[0], result[-1])
    [4.85, ..., 84.98]
    """
    n = len(x)
    r = int(numpy.ceil(f * n))
    h = [numpy.sort(abs(x - x[i]))[r] for i in range(n)]
    w = numpy.clip(abs(([x] - numpy.transpose([x])) / h), 0.0, 1.0)
    w = 1 - w * w * w
    w = w * w * w
    yest = numpy.zeros(n)
    delta = numpy.ones(n)
    for iteration in range(iter):
        for i in xrange(n):
            weights = delta * w[:, i]
            weights_mul_x = weights * x
            b1 = numpy.dot(weights, y)
            b2 = numpy.dot(weights_mul_x, y)
            A11 = sum(weights)
            A12 = sum(weights_mul_x)
            A21 = A12
            A22 = numpy.dot(weights_mul_x, x)
            determinant = A11 * A22 - A12 * A21
            beta1 = (A22 * b1 - A12 * b2) / determinant
            beta2 = (A11 * b2 - A21 * b1) / determinant
            yest[i] = beta1 + beta2 * x[i]
        residuals = y - yest
        s = median(abs(residuals))
        delta[:] = numpy.clip(residuals / (6 * s), -1, 1)
        delta[:] = 1 - delta * delta
        delta[:] = delta * delta
    return yest

    def mouseMoveEvent(self, ev):
        if self.lastMousePos is None:
            self.lastMousePos = Point(ev.pos())
        delta = Point(ev.pos() - self.lastMousePos)
        self.lastMousePos = Point(ev.pos())

        QtGui.QGraphicsView.mouseMoveEvent(self, ev)
        if not self.mouseEnabled:
            return
        self.sigSceneMouseMoved.emit(self.mapToScene(ev.pos()))

        if self.clickAccepted:  ## Ignore event if an item in the scene has already claimed it.
            return

        if ev.buttons() == QtCore.Qt.RightButton:
            delta = Point(np.clip(delta[0], -50, 50), np.clip(-delta[1], -50, 50))
            scale = 1.01 ** delta
            self.scale(scale[0], scale[1], center=self.mapToScene(self.mousePressPos))
            self.sigRangeChanged.emit(self, self.range)

        elif ev.buttons() in [QtCore.Qt.MidButton, QtCore.Qt.LeftButton]:  ## Allow panning by left or mid button.
            px = self.pixelSize()
            tr = -delta * px

            self.translate(tr[0], tr[1])
            self.sigRangeChanged.emit(self, self.range)

    def _compute_normalized_data(self, data_array):
        """
        Apply `data_func`, then linearly scale to the unit interval, and
        then apply `unit_func`.
        """
        
        # FIXME: Deal with nans?

        if self._dirty:
            self._recalculate()

        if self.data_func is not None:
            data_array = self.data_func(data_array)
            low, high = self.transformed_bounds
        else:
            low, high = self.range.low, self.range.high
        range_diff = high - low

        # Linearly transform the values to the unit interval.        

        if range_diff == 0.0 or isinf(range_diff):
            # Handle null range, or infinite range (which can happen during 
            # initialization before range is connected to a data source).
            norm_data = 0.5*ones_like(data_array)
        else:
            norm_data = empty(data_array.shape, dtype='float32')
            norm_data[:] = data_array
            norm_data -= low
            norm_data /= range_diff
            clip(norm_data, 0.0, 1.0, norm_data)

        if self.unit_func is not None:
            norm_data = self.unit_func(norm_data)

        return norm_data

 def numpy_run(self):
     """Forward propagation from batch on CPU only.
     """
     super(All2AllStrictRELU, self).numpy_run()
     self.output.map_write()
     mem = self.output.mem
     numpy.clip(mem, 0.0, 1.0e30, mem)

def isotonic_regression(y, sample_weight=None, y_min=None, y_max=None,
                        increasing=True):
    """Solve the isotonic regression model::

        min sum w[i] (y[i] - y_[i]) ** 2

        subject to y_min = y_[1] <= y_[2] ... <= y_[n] = y_max

    where:
        - y[i] are inputs (real numbers)
        - y_[i] are fitted
        - w[i] are optional strictly positive weights (default to 1.0)

    Read more in the :ref:`User Guide <isotonic>`.

    Parameters
    ----------
    y : iterable of floating-point values
        The data.

    sample_weight : iterable of floating-point values, optional, default: None
        Weights on each point of the regression.
        If None, weight is set to 1 (equal weights).

    y_min : optional, default: None
        If not None, set the lowest value of the fit to y_min.

    y_max : optional, default: None
        If not None, set the highest value of the fit to y_max.

    increasing : boolean, optional, default: True
        Whether to compute ``y_`` is increasing (if set to True) or decreasing
        (if set to False)

    Returns
    -------
    y_ : list of floating-point values
        Isotonic fit of y.

    References
    ----------
    "Active set algorithms for isotonic regression; A unifying framework"
    by Michael J. Best and Nilotpal Chakravarti, section 3.
    """
    order = np.s_[:] if increasing else np.s_[::-1]
    y = np.array(y[order], dtype=np.float64)
    if sample_weight is None:
        sample_weight = np.ones(len(y), dtype=np.float64)
    else:
        sample_weight = np.array(sample_weight[order], dtype=np.float64)

    _inplace_contiguous_isotonic_regression(y, sample_weight)
    if y_min is not None or y_max is not None:
        # Older versions of np.clip don't accept None as a bound, so use np.inf
        if y_min is None:
            y_min = -np.inf
        if y_max is None:
            y_max = np.inf
        np.clip(y, y_min, y_max, y)
    return y[order]

def lossFun(inputs, targets, hprev):
  """
  inputs,targets are both list of integers.
  hprev is Hx1 array of initial hidden state
  returns the loss, gradients on model parameters, and last hidden state
  """
  xs, hs, ys, ps = {}, {}, {}, {}
  hs[-1] = np.copy(hprev)
  loss = 0
  # forward pass
  for t in xrange(len(inputs)):
    xs[t] = np.zeros((vocab_size,1)) # encode in 1-of-k representation
    xs[t][inputs[t]] = 1
    hs[t] = np.tanh(np.dot(Wxh, xs[t]) + np.dot(Whh, hs[t-1]) + bh) # hidden state
    ys[t] = np.dot(Why, hs[t]) + by # unnormalized log probabilities for next chars
    ps[t] = np.exp(ys[t]) / np.sum(np.exp(ys[t])) # probabilities for next chars
    loss += -np.log(ps[t][targets[t],0]) # softmax (cross-entropy loss)
  # backward pass: compute gradients going backwards
  dWxh, dWhh, dWhy = np.zeros_like(Wxh), np.zeros_like(Whh), np.zeros_like(Why)
  dbh, dby = np.zeros_like(bh), np.zeros_like(by)
  dhnext = np.zeros_like(hs[0])
  for t in reversed(xrange(len(inputs))):
    dy = np.copy(ps[t])
    dy[targets[t]] -= 1 # backprop into y
    dWhy += np.dot(dy, hs[t].T)
    dby += dy
    dh = np.dot(Why.T, dy) + dhnext # backprop into h
    dhraw = (1 - hs[t] * hs[t]) * dh # backprop through tanh nonlinearity
    dbh += dhraw
    dWxh += np.dot(dhraw, xs[t].T)
    dWhh += np.dot(dhraw, hs[t-1].T)
    dhnext = np.dot(Whh.T, dhraw)
  for dparam in [dWxh, dWhh, dWhy, dbh, dby]:
    np.clip(dparam, -5, 5, out=dparam) # clip to mitigate exploding gradients
  return loss, dWxh, dWhh, dWhy, dbh, dby, hs[len(inputs)-1]

	def _raisePermanenceToThreshold(self, perm, mask):
	    """
	    This method ensures that each column has enough connections to input bits
	    to allow it to become active. Since a column must have at least
	    'self._stimulusThreshold' overlaps in order to be considered during the
	    inhibition phase, columns without such minimal number of connections, even
	    if all the input bits they are connected to turn on, have no chance of
	    obtaining the minimum threshold. For such columns, the permanence values
	    are increased until the minimum number of connections are formed.


	    Parameters:
	    ----------------------------
	    @param perm:    An array of permanence values for a column. The array is
	                    "dense", i.e. it contains an entry for each input bit, even
	                    if the permanence value is 0.
	    @param mask:    the indices of the columns whose permanences need to be
	                    raised.
	    """
	    if len(mask) < self._stimulusThreshold:
	        raise Exception("This is likely due to a " +
	        "value of stimulusThreshold that is too large relative " +
	        "to the input size. [len(mask) < self._stimulusThreshold]")

	    numpy.clip(perm, self._synPermMin, self._synPermMax, out=perm)
	    while True:
	        numConnected = numpy.nonzero(perm > self._synPermConnected)[0].size
	        if numConnected >= self._stimulusThreshold:
	            return
	        perm[mask] += self._synPermBelowStimulusInc

 def K(self, X, X2=None,alpha=None,variance=None):
     """
     Computes the covariance matrix cov(X[i,:],X2[j,:]).
     
     Args:
         X: Matrix where each row is a point.
         X2: Matrix where each row is a point.
         alpha: It's the scaled alpha.
         Variance: Sigma hyperparameter.
         
     """
     if alpha is None:
         alpha=self.alpha
     if variance is None:
         variance=self.variance
     
     if X2 is None:
         X=X*alpha/self.scaleAlpha
         Xsq=np.sum(np.square(X), 1)
         r=-2.*np.dot(X, X.T) + (Xsq[:, None] + Xsq[None, :])
         r = np.clip(r, 0, np.inf)
         return variance*np.exp(-0.5*r)
     else:
         X=X*alpha/self.scaleAlpha
         X2=X2*alpha/self.scaleAlpha
         r=-2.*np.dot(X, X2.T) + (np.sum(np.square(X), 1)[:, None] + np.sum(np.square(X2), 1)[None, :])
         r = np.clip(r, 0, np.inf)
         return variance*np.exp(-0.5*r)

def test_special_sparse_dot():
    # Test the function that computes np.dot(W, H), only where X is non zero.
    n_samples = 10
    n_features = 5
    n_components = 3
    rng = np.random.mtrand.RandomState(42)
    X = rng.randn(n_samples, n_features)
    np.clip(X, 0, None, out=X)
    X_csr = sp.csr_matrix(X)

    W = np.abs(rng.randn(n_samples, n_components))
    H = np.abs(rng.randn(n_components, n_features))

    WH_safe = nmf._special_sparse_dot(W, H, X_csr)
    WH = nmf._special_sparse_dot(W, H, X)

    # test that both results have same values, in X_csr nonzero elements
    ii, jj = X_csr.nonzero()
    WH_safe_data = np.asarray(WH_safe[ii, jj]).ravel()
    assert_array_almost_equal(WH_safe_data, WH[ii, jj], decimal=10)

    # test that WH_safe and X_csr have the same sparse structure
    assert_array_equal(WH_safe.indices, X_csr.indices)
    assert_array_equal(WH_safe.indptr, X_csr.indptr)
    assert_array_equal(WH_safe.shape, X_csr.shape)

 def _clipToSafeRange(min_, max_, isLog):
     # Clip range if needed
     minLimit = FLOAT32_MINPOS if isLog else FLOAT32_SAFE_MIN
     min_ = numpy.clip(min_, minLimit, FLOAT32_SAFE_MAX)
     max_ = numpy.clip(max_, minLimit, FLOAT32_SAFE_MAX)
     assert min_ < max_
     return min_, max_

def combine_images(imgs, alphas):
    """ Combine multiple rgb images in one rgb image """
    image_f = numpy.zeros(imgs[0].shape, dtype='float')
    for i in range(0, len(imgs)):
        image_f += alphas[i] * imgs[i]
    numpy.clip(image_f, 0., 255., image_f)
    return numpy.array(image_f, dtype='uint8')

def _compute_disk_overlap(d, r1, r2):
    """
    Compute surface overlap between two disks of radii ``r1`` and ``r2``,
    with centers separated by a distance ``d``.

    Parameters
    ----------
    d : float
        Distance between centers.
    r1 : float
        Radius of the first disk.
    r2 : float
        Radius of the second disk.

    Returns
    -------
    vol: float
        Volume of the overlap between the two disks.
    """

    ratio1 = (d ** 2 + r1 ** 2 - r2 ** 2) / (2 * d * r1)
    ratio1 = np.clip(ratio1, -1, 1)
    acos1 = math.acos(ratio1)

    ratio2 = (d ** 2 + r2 ** 2 - r1 ** 2) / (2 * d * r2)
    ratio2 = np.clip(ratio2, -1, 1)
    acos2 = math.acos(ratio2)

    a = -d + r2 + r1
    b = d - r2 + r1
    c = d + r2 - r1
    d = d + r2 + r1
    area = (r1 ** 2 * acos1 + r2 ** 2 * acos2 -
            0.5 * sqrt(abs(a * b * c * d)))
    return area / (math.pi * (min(r1, r2) ** 2))

def interpgrid(a, xi, yi):
    """Fast 2D, linear interpolation on an integer grid"""

    Ny, Nx = np.shape(a)
    if isinstance(xi, np.ndarray):
        x = xi.astype(np.int)
        y = yi.astype(np.int)
        # Check that xn, yn don't exceed max index
        xn = np.clip(x + 1, 0, Nx - 1)
        yn = np.clip(y + 1, 0, Ny - 1)
    else:
        x = np.int(xi)
        y = np.int(yi)
        # conditional is faster than clipping for integers
        if x == (Nx - 2): xn = x
        else: xn = x + 1
        if y == (Ny - 2): yn = y
        else: yn = y + 1

    a00 = a[y, x]
    a01 = a[y, xn]
    a10 = a[yn, x]
    a11 = a[yn, xn]
    xt = xi - x
    yt = yi - y
    a0 = a00 * (1 - xt) + a01 * xt
    a1 = a10 * (1 - xt) + a11 * xt
    ai = a0 * (1 - yt) + a1 * yt

    if not isinstance(xi, np.ndarray):
        if np.ma.is_masked(ai):
            raise TerminateTrajectory

    return ai

    def rmsprop_one_step(self, param_name, index, grad_args, decay = 0.9, momentum = 0, learning_rate_adapt = 0.05, 
        learning_rate_min = 1e-6, learning_rate_max = 10):
        # RMSPROP: Tieleman, T. and Hinton, G. (2012), Lecture 6.5 - rmsprop, COURSERA: Neural Networks for Machine Learning
        # Implementation based on https://github.com/BRML/climin/blob/master/climin/rmsprop.py
        
        # We use Nesterov momentum: first, we make a step according to the momentum and then we calculate the gradient.
        step1 = self.param_updates[param_name] * momentum
        self.wrt[param_name].set_value(self.wrt[param_name].get_value()+step1)
        grad = self.get_grad(*grad_args)

        self.moving_mean_squared[param_name] = (decay * self.moving_mean_squared[param_name] + (1 - decay) * grad ** 2)
        step2 = self.learning_rates[param_name] * grad / (self.moving_mean_squared[param_name] + 1e-8)**0.5

        # DEBUG
        if param_name == 'lhyp' or 'ls':
            step2 = np.clip(step2, -0.1, 0.1)
        
        self.wrt[param_name].set_value(self.wrt[param_name].get_value()+step2)
        #self.params[param_name] += step2

        step = step1 + step2

        # Step rate adaption. If the current step and the momentum agree, we slightly increase the step rate for that dimension.
        if learning_rate_adapt:
            # This code might look weird, but it makes it work with both numpy and gnumpy.
            step_non_negative = step > 0
            step_before_non_negative = self.param_updates[param_name] > 0
            agree = (step_non_negative == step_before_non_negative) * 1.#０か１が出る
            adapt = 1 + agree * learning_rate_adapt * 2 - learning_rate_adapt
            self.learning_rates[param_name] *= adapt
            self.learning_rates[param_name] = np.clip(self.learning_rates[param_name], learning_rate_min, learning_rate_max)

        self.param_updates[param_name] = step

    def updateParticles(self):
        # Update positions with velocity
        self.particles[:, 0:2] += self.particles[:, 4:6]
        #np.clip(self.particles[:,0], 0, self.bounds[0], self.particles[:,0])
        #np.clip(self.particles[:,1], 0, self.bounds[1], self.particles[:,1])

        # Add noise to w,h
        if self.SIGMA_size > 0.0001:
            self.particles[:, 2:4] += random.normal(0, self.SIGMA_size, (self.particles.shape[0], 2))
        #np.clip(self.particles[:,2], 1, self.bounds[0], self.particles[:,2])
        #np.clip(self.particles[:,3], 1, self.bounds[1], self.particles[:,3])
        # Add noise to velocities and clip
        self.particles[:, 4:6] += random.normal(
            0, self.SIGMA_velocity, (self.particles.shape[0], 2))
        #np.clip(self.particles[:,4:6], -MAX_velocity,MAX_velocity, self.particles[:,4:6])

        lb = [0, 0, 1, 1, -MAX_velocity, -MAX_velocity, 0]
        ub = [self.bounds[1],
              self.bounds[0],
              self.bounds[1],
              self.bounds[0],
              MAX_velocity,
              MAX_velocity,
              1]
        np.clip(self.particles, lb, ub, self.particles)
        if np.max(self.particles[:, 0]) > self.bounds[1]:
            print "Not clipped"
        self.iterations += 1