import tecplot as tp
import os
import numpy as np

# Load transient flow past cylinder
examples_dir = tp.session.tecplot_examples_directory()
datafile = os.path.join(examples_dir, 'SimpleData', 'VortexShedding.plt')
tp.data.load_tecplot(datafile)

# Get Frame, plot and dataset handles 
frame = tp.active_frame()
plot = frame.plot()
ds = frame.dataset

# Duplicate the first zone which becomes the last zone
avg_zone = ds.zone(0).copy()
avg_zone.name = "Averaged Zone"
avg_zone.strand = 0         # Using Strand = 0 sets this as a new fieldmap
avg_zone.solution_time = 0.0    # Averaged zone does not have time step

# Generate a matrix for each variable, zones by points. Then average
# (using numpy average) across all zones to get the by point value

for var in list(ds.variables())[2:]:  # Use to skip XYZ coords
    a = np.empty([ds.num_zones -1, avg_zone.num_points])
    for z in list(ds.zones())[:-1]:   # Skip duplicated zone
        values= z.values(var).as_numpy_array() # Get value at all locations
        a[z.index,:] = values         # Build matrix
    avg = np.average(a, axis=0)       # Average across all zones
    avg_zone.values(var)[:] = avg     # Add average to duplicated zone

tp.data.save_tecplot_plt('vortex_with_average.plt')

# Delete textboxes setup for LPK
for txt in frame.texts():
    frame.delete_text(txt)
    
# Turn on the averaged zone only.
for fmap in plot.fieldmaps():
    fmap.show = False

plot.show_contour = True
plot.contour(0).variable = ds.variable('T(K)')
plot.fieldmap(avg_zone).show = True
plot.fieldmap(avg_zone).contour.show = True

plot.axes.y_axis.min = -0.02
plot.axes.y_axis.max = 0.02
plot.axes.x_axis.min = -0.008
plot.axes.x_axis.max = 0.04

tp.export.save_png('avg_vortex.png', width=800, supersample=3)