contourf doesn't plot left side of the figure in log scale!

consider the code:

close all;
clear;
clc;

Elasticity = 58.34E9; %  GPa

[force, radius] = meshgrid(linspace(0, 1), linspace(1, 60) * 1E-3); %  [N, m]

delta = (3 * force / 4 / Elasticity).^(2 / 3) ./ (radius).^(1 / 3);
stiffness = 2 * Elasticity * sqrt(radius .* delta);
pressure = (6 * force .* (Elasticity ./ radius).^2).^(1 / 3) / pi;

stiffness_min = (1000 * 2 * pi)^2 * 0.150 / 3;
stiffness_plot = stiffness;
stiffness_plot(stiffness < stiffness_min) = nan;
stiffness_plot(503E6 < pressure) = nan;

contourf(force, radius, stiffness_plot, 'ShowText', 'on');
set(gca, 'XScale', 'log');
xlim([0.01 force(end)])

the result is

as expected. However if I change the line

[force, radius] = meshgrid(linspace(0, 10), linspace(1, 60) * 1E-3); %  [N, m]

I get the plot:

where the left side of th efigure is missing. I would appreciate if you could help me know what is the problem and how I can fix it.

Answer 1

[Star Strider]

The problem is the resolution in the ‘force’ vector.

For example, check the increments —

format long
f1 = mean(diff(linspace(0, 1)))

f1 = 
   0.010101010101010

f2 = mean(diff(linspace(0, 10)))

f2 = 
   0.101010101010101

f3 = mean(diff(linspace(0, 10, 1000)))

f3 = 
   0.010010010010010

format short

Increasing the number of elements in the (0, 10) linspace call, therefore approsimately restoring the original resolution, results in the original behaviour.

Elasticity = 58.34E9; %  GPa

[force, radius] = meshgrid(linspace(0, 10, 1000), linspace(1, 60) * 1E-3); %  [N, m]

delta = (3 * force / 4 / Elasticity).^(2 / 3) ./ (radius).^(1 / 3);
stiffness = 2 * Elasticity * sqrt(radius .* delta);
pressure = (6 * force .* (Elasticity ./ radius).^2).^(1 / 3) / pi;

stiffness_min = (1000 * 2 * pi)^2 * 0.150 / 3;
stiffness_plot = stiffness;
stiffness_plot(stiffness < stiffness_min) = nan;
stiffness_plot(503E6 < pressure) = nan;

contourf(force, radius, stiffness_plot, 'ShowText', 'on');
set(gca, 'XScale', 'log');
xlim([0.01 force(end)])

.