# Phase Fractions at Constant X or T¶

In the following example, we demonstrate the simultaneous calculation of line phase equilibria for multiple Gibbs energy parameter sets in CALPHAD using PDUQ, followed by a visualization.

## Set-up¶

In this example we will reuse the eq file from the previous example where we performed UQ tasks on the full Cu-Mg phase diagram.

First, we import the plot_phasefracline function from the uq_plot module.

```
from pduq.uq_plot import plot_phasefracline
```

## Data Analysis and Plotting¶

Let us start by plotting the phase fraction as it varies with temperature with the composition fixed at 0.1 molar fraction Mg.

```
# define a dictionary fixing the composition. We need to pick
# a value for X_MG that is represented in the eq object
coordD = {'X_MG':0.1}
# plot the phase fraction versus composition
# cdict and phase_label_dict are the same as in the previous example
uq.plot_phasefracline(eq, coordD, xlabel='T (K)', cdict=cdict,
phase_label_dict=phase_label_dict, figsize=(5, 3))
```

resulting in the following figure

Next we plot the phase fraction as it varies with composition at 1000K.

```
# define a dictionary fixing the temperature. We need to pick
# a value for T that is represented in the eq object
coordD = {'T':1000}
# plot the phase fraction versus composition
# cdict and phase_label_dict are the same as in the previous example
uq.plot_phasefracline(eq, coordD, xlabel=r"$x_{Mg}$", cdict=cdict,
phase_label_dict=phase_label_dict, figsize=(5, 3))
```

resulting in the following figure