modeling device using Verilog-A and having convergence problems

Hi,

I'm new to Verilog-A I am having convergence issues with a device I modeled in Verilog-A. When I have the device simulated in parallel with a time varying voltage source then the simulation seems to work okay. The issues arise when I try to simulate transient behaviour of my device in series with an added resistor and the voltage source in parallel with both the series resistor and Verilog-A device (as seen in image if I added it correctly).

The code for the device is below.

[CODE]
`include "constants.vams"
`include "disciplines.vams"

module test_func(p,n);

    inout p,n;
    electrical p,n;

    //files for reading/writing
    integer mcd, fp;

    real data, v_present, v_step;

    real preisach_density[0:256];// all elements should add up to 1
    real domain_states[0:256];// all elements should be -1 or +1 (depending on polarity)
    real polarization;//polarization (between -Pr and +Pr)
    
    real polarization_prev, polarization_next;
    real time_prev, time_next;

    integer i, j, k;//used in loops

    integer rows, columns;//describes area scanned from applied voltage
    integer rows_total, columns_total;//gives number of rows and columns in the grid ("rows" and "columns" should not exceed these values)
    
    analog begin    

        @(initial_step) begin

            //read data from csv file and transfer it to verilog-A array variable
            //data stored in csv file should be preisach distribution
            //csv file should have the same number of elements as arrays "preisach_density" and "domain_states"
            mcd=$fopen("test6.csv","r");

            while (!$feof(mcd)) begin

                $fscanf(mcd,"%f", preisach_density[i]);
                domain_states[i] = 1;

                i = i+1;
                  end

        //****************** v_step should be changed, should equal resolition of grid spacing
        v_step = 0.1; //arbitrary

        rows_total = 1.6/v_step;//the maximum anticipated applied input voltage divided by the resolution of the grid cells
        columns_total = 1.6/v_step;//the minimum anticipated applied input voltage divided by the resolution of the grid cells

        polarization_prev = 0;

        time_prev = 0;
        time_next = 0;
        
        end

        if (V(p,n) < 0) begin

            rows = V(p,n)/(-v_step);

            for(j = 0; j < columns_total; j=j+1) begin

                for(k=0; k<rows; k=k+1) begin

                    domain_states[k*columns_total + j] = -1;

                end
            end
        end

        if (V(p,n) > 0) begin

            columns = V(p,n)/(v_step);

            //value compared to j should equal number of columns in array
            for (j=0; j<columns * rows_total ; j=j+1) begin

                domain_states[j] = 1;

            end
        end

        polarization = 0;
        for (i=0; i<columns_total*rows_total; i = i+1) begin

            polarization = polarization + preisach_density[i]*domain_states[i];

        end

        
        polarization_prev = polarization_next;
        polarization_next = polarization;
        time_prev = time_next;
        time_next = $abstime;

        I(p,n) <+ (polarization_next - polarization_prev)/(time_next - time_prev);

    end

endmodule
[/CODE]

The error I get is:

Error (SPECTRE-16080): No DC solution found

I also get "Array access out of bounds" errors when the device is simulated in the circuit shown but this does not occur when it's just the device in parallel with the voltage source with no resistor. Does anyone have suggestions for how I can solve these issues?