def simplegrid():
nzones = 7
gr = gpu.grid(nzones, xmin=0, xmax=1)
gpu.drawGrid(gr, edgeTicks=0)
# label a few cell-centers
gpu.labelCenter(gr, nzones/2, r"$i$")
gpu.labelCenter(gr, nzones/2-1, r"$i-1$")
gpu.labelCenter(gr, nzones/2+1, r"$i+1$")
# label a few edges
gpu.labelEdge(gr, nzones/2, r"$i-1/2$")
gpu.labelEdge(gr, nzones/2+1, r"$i+1/2$")
# draw an average quantity
gpu.drawCellAvg(gr, nzones/2, 0.4, color="r")
gpu.labelCellAvg(gr, nzones/2, 0.4, r"$\,\langle a \rangle_i$", color="r")
pylab.axis([gr.xmin-1.5*gr.dx,gr.xmax+1.5*gr.dx, -0.25, 1.5])
pylab.axis("off")
pylab.subplots_adjust(left=0.05,right=0.95,bottom=0.05,top=0.95)
f = pylab.gcf()
f.set_size_inches(10.0,2.5)
pylab.savefig("simplegrid2.png")
pylab.savefig("simplegrid2.eps")
gpu.labelCenter(gr, nzones/2, r"$i$")
gpu.labelCenter(gr, nzones/2-1, r"$i-1$")
gpu.labelCenter(gr, nzones/2+1, r"$i+1$")
gpu.labelCenter(gr, nzones/2-2, r"$i-2$")
gpu.labelCenter(gr, nzones/2+2, r"$i+2$")
gpu.labelEdge(gr, nzones/2, r"$i-1/2$")
gpu.labelEdge(gr, nzones/2+1, r"$i+1/2$")
# draw the data
i = 0
while i < nzones:
gpu.drawCellAvg(gr, i, a[i], color="r")
i += 1
gpu.labelCellAvg(gr, nzones/2, a[nzones/2], r"$\langle f\rangle_i$", color="r")
# label dx
pylab.plot([gr.xr[gr.ng+nzones/2-1], gr.xr[gr.ng+nzones/2-1]], [-0.35,-0.25], color="k")
pylab.plot([gr.xr[gr.ng+nzones/2], gr.xr[gr.ng+nzones/2]], [-0.35,-0.25], color="k")
pylab.plot([gr.xr[gr.ng+nzones/2-1], gr.xr[gr.ng+nzones/2]], [-0.3,-0.3], color="k")
pylab.text(gr.xc[gr.ng+nzones/2], -0.45, r"$\Delta x$",
horizontalalignment="center")
pylab.axis([gr.xmin-0.5*gr.dx,gr.xmax+0.5*gr.dx, -0.5, 1.2])
pylab.axis("off")
pylab.subplots_adjust(left=0.05,right=0.95,bottom=0.05,top=0.95)
gpu.labelCenter(gr, gr.ilo-2, r"$\mathrm{lo-2}$")
gpu.labelCenter(gr, gr.ihi, r"$\mathrm{hi}$")
gpu.labelCenter(gr, gr.ihi+1, r"$\mathrm{hi+1}$")
gpu.labelCenter(gr, gr.ihi+2, r"$\mathrm{hi+2}$")
gpu.labelEdge(gr, ng+nzones/2, r"$i-1/2$")
gpu.labelEdge(gr, ng+nzones/2+1, r"$i+1/2$")
# draw the data
i = 0
while i < nzones:
gpu.drawCellAvg(gr, ng+i, a[i], color="r")
i += 1
gpu.labelCellAvg(gr, ng+nzones/2, a[nzones/2], r"$\langle a\rangle_i$", color="r")
# label dx
pylab.plot([gr.xr[gr.ng+nzones/2-1], gr.xr[gr.ng+nzones/2-1]], [-0.35,-0.25], color="k")
pylab.plot([gr.xr[gr.ng+nzones/2], gr.xr[gr.ng+nzones/2]], [-0.35,-0.25], color="k")
pylab.plot([gr.xr[gr.ng+nzones/2-1], gr.xr[gr.ng+nzones/2]], [-0.3,-0.3], color="k")
pylab.text(gr.xc[gr.ng+nzones/2], -0.55, r"$\Delta x$",
horizontalalignment="center", fontsize=16)
pylab.axis([gr.xmin-2.02*gr.dx,gr.xmax+2.02*gr.dx, -0.5, 1.6])
pylab.axis("off")
pylab.subplots_adjust(left=0.025,right=0.975,bottom=0.05,top=0.95)
gpu.labelEdge(gr, ng + ncells / 2, r"$i-1/2$")
gpu.labelEdge(gr, ng + ncells / 2 + 1, r"$i+1/2$")
gpu.labelEdge(gr, ng + gr.nx, r"$b$")
gpu.labelEdge(gr, ng + 0, r"$a$")
# draw the data
i = 0
while i < ncells + 2 * ng:
gpu.drawCellAvg(gr, i, acell[i], color="r")
i += 1
gpu.labelCellAvg(gr,
ng + ncells / 2,
acell[ng + ncells / 2],
r"$\langle f\rangle_i$",
color="r")
# label dx
pylab.plot([gr.xr[gr.ng + ncells / 2 - 1], gr.xr[gr.ng + ncells / 2 - 1]],
[-0.35, -0.25],
color="k")
pylab.plot([gr.xr[gr.ng + ncells / 2], gr.xr[gr.ng + ncells / 2]],
[-0.35, -0.25],
color="k")
pylab.plot([gr.xr[gr.ng + ncells / 2 - 1], gr.xr[gr.ng + ncells / 2]],
[-0.3, -0.3],
color="k")
pylab.text(gr.xc[gr.ng + ncells / 2],
-0.45,