util_functions.py

# utility functions
# modify from
# http://nbviewer.jupyter.org/github/julienr/ipynb_playground/blob/master/keras/convmnist/keras_cnn_mnist.ipynb
from mpl_toolkits.axes_grid1 import make_axes_locatable
import matplotlib.pyplot as pl
import numpy as np

def nice_imshow(ax, data, vmin=None, vmax=None, cmap=None):
    """Wrapper around pl.imshow"""
    if cmap is None:
        cmap = cm.jet
    if vmin is None:
        vmin = data.min()
    if vmax is None:
        vmax = data.max()
    divider = make_axes_locatable(ax)
    cax = divider.append_axes("right", size="5%", pad=0.05)
    im = ax.imshow(data, vmin=vmin, vmax=vmax, interpolation='nearest', cmap=cmap)
    pl.colorbar(im, cax=cax)

import numpy.ma as ma
def make_mosaic(imgs, nrows, ncols, border=1):
    """ Given a set of images with all the same shape, makes a mosaic with nrows and ncols """
    nimgs = imgs.shape[0]
    imshape = imgs.shape[1:]
    mosaic = ma.masked_all((nrows * imshape[0] + (nrows - 1) * border,
                                ncols * imshape[1] + (ncols - 1) * border),
                                                            dtype=np.float32)
                                                                
    paddedh = imshape[0] + border
    paddedw = imshape[1] + border
    for i in xrange(nimgs):
        row = int(np.floor(i / ncols))
        col = i % ncols         
        mosaic[row * paddedh:row * paddedh + imshape[0],
               col * paddedw:col * paddedw + imshape[1]] = imgs[i]
    return mosaic
#pl.imshow(make_mosaic(np.random.random((9, 10, 10)), 3, 3, border=1))