diff --git a/optimizedSD/optimized_txt2img.py b/optimizedSD/optimized_txt2img.py
index c82918240..ddfe31687 100644
--- a/optimizedSD/optimized_txt2img.py
+++ b/optimizedSD/optimized_txt2img.py
@@ -1,4 +1,6 @@
-import argparse, os, re
+import argparse
+import os
+import re
 import torch
 import numpy as np
 from random import randint
@@ -33,15 +35,48 @@ def load_model_from_config(ckpt, verbose=False):
     return sd
 
 
+def vectorize_prompt(modelCS, batch_size, prompt):
+    empty_result = modelCS.get_learned_conditioning(batch_size * [""])
+    result = torch.zeros_like(empty_result)
+    subprompts, weights = split_weighted_subprompts(prompt)
+    weights_sum = sum(weights)
+    cntr = 0
+    for i, subprompt in enumerate(subprompts):
+        cntr += 1
+        result = torch.add(result,
+                           modelCS.get_learned_conditioning(batch_size
+                                                            * [subprompt]),
+                           alpha=weights[i] / weights_sum)
+    if cntr == 0:
+        result = empty_result
+    return result
+
+
 config = "optimizedSD/v1-inference.yaml"
 DEFAULT_CKPT = "models/ldm/stable-diffusion-v1/model.ckpt"
 
 parser = argparse.ArgumentParser()
 
 parser.add_argument(
-    "--prompt", type=str, nargs="?", default="a painting of a virus monster playing guitar", help="the prompt to render"
+    "--prompt",
+    type=str,
+    nargs="?",
+    default="a painting of a virus monster playing guitar",
+    help="the prompt to render"
+)
+parser.add_argument(
+    "--nprompt",
+    type=str,
+    default="",
+    help="negative prompt to render"
+)
+parser.add_argument(
+    "--outdir",
+    type=str,
+    nargs="?",
+    help="dir to write results to",
+    default="outputs/txt2img-samples"
 )
-parser.add_argument("--outdir", type=str, nargs="?", help="dir to write results to", default="outputs/txt2img-samples")
 parser.add_argument(
     "--skip_grid",
     action="store_true",
@@ -58,7 +93,6 @@ def load_model_from_config(ckpt, verbose=False):
     default=50,
     help="number of ddim sampling steps",
 )
-
 parser.add_argument(
     "--fixed_code",
     action="store_true",
@@ -147,7 +181,7 @@ def load_model_from_config(ckpt, verbose=False):
     help="Reduces inference time on the expense of 1GB VRAM",
 )
 parser.add_argument(
-    "--precision", 
+    "--precision",
     type=str,
     help="evaluate at this precision",
     choices=["full", "autocast"],
@@ -164,7 +198,7 @@ def load_model_from_config(ckpt, verbose=False):
     "--sampler",
     type=str,
     help="sampler",
-    choices=["ddim", "plms","heun", "euler", "euler_a", "dpm2", "dpm2_a", "lms"],
+    choices=["ddim", "plms", "heun", "euler", "euler_a", "dpm2", "dpm2_a", "lms"],
     default="plms",
 )
 parser.add_argument(
@@ -185,7 +219,7 @@ def load_model_from_config(ckpt, verbose=False):
 seed_everything(opt.seed)
 
 # Logging
-logger(vars(opt), log_csv = "logs/txt2img_logs.csv")
+logger(vars(opt), log_csv="logs/txt2img_logs.csv")
 
 sd = load_model_from_config(f"{opt.ckpt}")
 li, lo = [], []
@@ -258,12 +292,12 @@ def load_model_from_config(ckpt, verbose=False):
 
 seeds = ""
 with torch.no_grad():
-
     all_samples = list()
     for n in trange(opt.n_iter, desc="Sampling"):
         for prompts in tqdm(data, desc="data"):
-
             sample_path = os.path.join(outpath, "_".join(re.split(":| ", prompts[0])))[:150]
+            if prompts[0] == "":
+                sample_path = os.path.join(outpath, "empty_prompt")
             os.makedirs(sample_path, exist_ok=True)
             base_count = len(os.listdir(sample_path))
 
@@ -271,22 +305,13 @@ def load_model_from_config(ckpt, verbose=False):
                 modelCS.to(opt.device)
                 uc = None
                 if opt.scale != 1.0:
-                    uc = modelCS.get_learned_conditioning(batch_size * [""])
+                    uc = vectorize_prompt(modelCS, batch_size, opt.nprompt)
                 if isinstance(prompts, tuple):
                     prompts = list(prompts)
+                c = vectorize_prompt(modelCS, batch_size, prompts[0])
 
-                subprompts, weights = split_weighted_subprompts(prompts[0])
-                if len(subprompts) > 1:
-                    c = torch.zeros_like(uc)
-                    totalWeight = sum(weights)
-                    # normalize each "sub prompt" and add it
-                    for i in range(len(subprompts)):
-                        weight = weights[i]
-                        # if not skip_normalize:
-                        weight = weight / totalWeight
-                        c = torch.add(c, modelCS.get_learned_conditioning(subprompts[i]), alpha=weight)
-                else:
-                    c = modelCS.get_learned_conditioning(prompts)
+                # vectorize_prompt() (see above) replaces the existing code.
+                # vectorize_prompt() by https://github.com/consciencia/stable-diffusion
 
                 shape = [opt.n_samples, opt.C, opt.H // opt.f, opt.W // opt.f]
 
@@ -306,7 +331,7 @@ def load_model_from_config(ckpt, verbose=False):
                     unconditional_conditioning=uc,
                     eta=opt.ddim_eta,
                     x_T=start_code,
-                    sampler = opt.sampler,
+                    sampler=opt.sampler,
                 )
 
                 modelFS.to(opt.device)