minor edits

docs/pages/add_block.md

@@ -53,36 +53,27 @@ Below are details on the steps required to implement a new block in svZeroDSolve
 
 <p> <br> </p>
 
-* *(Optional)* The class can have an `enum ParamId` object that relates the parameter indices to their names. 
+* *Optional:* The class can have an `enum ParamId` object that relates the parameter indices to their names. 
  * This makes it easier to reference the parameters while implementing the governing equations of the block (discussed below). 
  * The order of parameters in the `ParamId` object should match the order in the constructor. 
 
 <p> <br> </p>
 
 # 3. Set up the governing equations for the block.
 
-* The local state vector for each block is always arranged as `[P_in, Q_in, P_out, Q_out, InternalVariable_1, ..., InternalVariable_N]`. 
-
+* The local state vector for each block is always arranged as `[P_in, Q_in, P_out, Q_out, InternalVariable_1, ..., InternalVariable_N]`. 
  * Here, `InternalVariable*` refers to any variable in the governing equations that are not the inlet and outlet flow and pressure. These are the same as those discussed above in the function `setup_dofs`.
-
  * The length of the state vector is typically four (inlet and outlet pressure and flow) plus the number of internal variables.
 
 <p> <br> </p>
 
 * The equations should be written in the form `E(t)*ydot + F(t)*y + C(y,t) = 0`. 
-
  * `y` is the local state vector mentioned above 
-
  * `ydot` is the time-derivative of the local state vector 
-
  * `E` and `F` are matrices of size `number_of_equations*size_of_state_vector`. 
-
  * `c` is a vector of length `number_of_equations`. 
-
  * `E` and `F` contain terms of the governing equation that multiply the respective components of `ydot` and `y` respectively.
-
  * `C` is a vector containing all non-linear and constant terms in the equation. 
-
  * If the equation contains non-linear terms, the developer should also derive the derivative of `C` with respect to `y` and `ydot`. These will be stored in the block's `dC_dy` and `dC_dydot` matrices, both of which are size `number_of_equations*size_of_state_vector`.
 
 <p> <br> </p>
@@ -94,33 +85,21 @@ a*dQ_in/dt + b*P_in + c*(dP_in/dt)*Q_in + d = 0
 ```
 e*dP_out/dt + f*Q_out*Q_out + g*P_out + h*I_1 = 0
 ```
-
  * For this block, the `P_in` and `Q_in` are the pressure and flow at the inlet respectively, `P_out` and `Q_out` are the pressure and flow at the outlet, and `I_1` is an internal variable.
-
  * The state vector is `[P_in, Q_in, P_out, Q_out, I_1]`.
-
  * The contributions to the local `F` matrix are `F[0,0] = b`, `F[1,2] = g` and `F[1,4] = h`.
-
  * The contributions to the local `E` matrix are `E[0,1] = a` and `E[1,2] = e`.
-
  * The contributions to the local `C` vector are `C[0] = c*(dP_in/dt)*Q_in + d` and `C[1] = f*Q_out*Q_out`.
-
  * The contributions to the local `dC_dy` matrix are `dC_dy[0,1] = c*(dP_in/dt)` and `dC_dy[1,3] = 2*f*Q_out`.
-
  * The contributions to the local `dC_dydot` matrix are `dC_dydot[0,0] = c*Q_in`.
-
  * In this case, the block has 3 contributions to `F`, 2 contributions to `E`, and 2 constributions to `dC_dy`. So the class will have a member `TripletsContributions num_triplets{3, 2, 2}`.
 
 # 4. Implement the matrix equations for the block.
 
 * Implement the `update_constant`, `update_time` and `update_solution` functions.
-
  * All matrix elements that are constant are specified in `update_constant`.
-
  * Matrix elements that depend only on time (not the solution of the problem itself) are specified in `update_time`. 
-
  * Matrix elements that change with the solution (i.e. depend on the state variables themselves) are specified in `update_solution`. 
-
  * Not all blocks will require the `update_time` and `update_solution` functions.
 
 <p> <br> </p>
@@ -129,24 +108,23 @@ e*dP_out/dt + f*Q_out*Q_out + g*P_out + h*I_1 = 0
 ```
 system.F.coeffRef(global_eqn_ids[current_block_equation_id], global_var_ids[current_block_variable_ids]) = a
 ```
-
  * Here, `current_block_equation_id` goes from 0 to `number_of_equations-1` (for the current block) and `current_block_variable_ids` goes from 0 to `size_of_state_vector-1` for the current block. 
 
 <p> <br> </p>
 
-* If the block contains non-linear equations, these terms must be specified in `update_solution` as `system.C(global_eqn_ids[current_block_equation_id]) = non_linear_term`.
+* If the block contains non-linear equations, these terms must be specified in `update_solution` as 
+```
+system.C(global_eqn_ids[current_block_equation_id]) = non_linear_term
+```
 
 <p> <br> </p>
 
 * For non-linear equations, the derivative of the term specified above with respect to each state variable must also be provided. This goes into a `dC_dy` matrix using the following syntax 
 ```
 system.dC_dy.coeffRef(global_eqn_ids[current_block_equation_id], global_var_ids[current_block_variable_id]) = a
 ```
-
  * Here, `a` is the derivative of the non-linear term in the equation with ID `current_block_equation_id` with respect to the local state variable with ID `current_block_variable_id`. 
-
  * For example, if the non-linear term is in the first equation, `current_block_equation_id = 0`. 
-
  * For the derivative of this term with respect to `P_in`, `current_block_variable_id = 0` and for the derivative of this term with respect to `P_out`, `current_block_variable_id = 2`.
 
 <p> <br> </p>