Responses
Introduction
Physical quantity to optimize  Formula  Computation entity 

Torque on a mechanical set (virtual works) 
${T}_{m}=\frac{d{W}_{m}}{d\theta}$

On a mechanical set 
Torque ripple on a mechanical set (virtual works) 
$\u2206T=\left(\frac{{T}_{max}{T}_{min}}{{T}_{mean}}\right)*100$

On a mechanical set 
Force on a face region (virtual works) 
${F}_{x}=\frac{d{W}_{m}}{dx}$

On a face region 
Sum of the fluxes of selected coils 
$\phi =\sum _{i=1}^{n}{\phi}_{i}=L\sum _{i=1}^{n}{N}_{Si}\int {A}_{z}dS$

On one or several coil conductor components 
Flux flowing through lines 
$\phi =L\left({A}_{z}\right({n}_{1}){A}_{z}({n}_{2}\left)\right)$

On a line 
Volume of 2D faces  On faces  
Force computed on a path (Maxwell tensor) 
$Fm=L\int \frac{{B}_{n}^{2}{B}_{t}^{2}}{{\mu}_{0}}dl$

Based on the Maxwell tensors approach, this method requires a
path in a front of a piece of iron (plunger for an actuator,
stator tooth ...) Attention: This method is valuable only along a path in a air or
vaccum region.

Torque computed on a path (Maxwell tensor) 
$Tm=LpR\int \frac{{B}_{n}{B}_{t}}{{\mu}_{0}}dl$

Based on the Maxwell's tensors, this method requires also a path in the airgap of a rotating machine, this path is automatically computed by Flux. 
Torque ripple computed on a path (Maxwell tensor) 
$\u2206T=\left(\frac{{T}_{max}{T}_{min}}{{T}_{mean}}\right)*100$

Based on the torque computation explained above, this method requires also a path in the airgap of a rotating machine, this path is automatically computed by Flux. 